Condensed Matter

New submissions

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New submissions for Fri, 22 Jun 18

[1]
Title: Transformations of Phosphorus under Pressure from Simple Cubic to Simple Hexagonal Structures via Incommensurately Modulations: Electronic Origin
Authors: V. F Degtyareva
Comments: 6 page, 6 figures, the 1st International Electronic Conference on Crystals 21-31 May 2018. arXiv admin note: substantial text overlap with arXiv:0911.2409
Journal-ref: Sciforum Electronic Conference Series, Vol. 1, 2018 10.3390/IECC 2018-05243
Subjects: Materials Science (cond-mat.mtrl-sci)

The lighter group-V element phosphorus forms the As-type (hR2) structure under pressure, above 5 GPa, and at 10 GPa transforms to the simple cubic structure (cP1), similar to arsenic. Despite of its low packing density, the simple cubic structure is stable in phosphorus over a very wide pressure range up to 103 GPa. On further pressure increase, the simple cubic structure transforms to a simple hexagonal structure (hP1) via a complex phase that was solved recently as incommensurately modulated. Structural transformations of phosphorus are connected with the changes of physical properties. Above 5 GPa phosphorus shows superconductivity with Tc reaching ~9.5K at 32GPa. The crystal structures and properties of high-pressure phases for phosphorus are discussed within the model of the Fermi sphere and Brillouin zone interactions.

[2]
Title: Nonlocal Spin Transport Mediated by a Vortex Liquid in Superconductors
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Superconductivity (cond-mat.supr-con)

Departing from the conventional view on superconducting vortices as a parasitic source of dissipation for charge transport, we propose to use mobile vortices as topologically-stable information carriers for spin transport. To this end, we start by constructing a phenomenological theory for the interconversion between spin and vorticity, a topological charge carried by vortices, at the interface between a magnetic insulator and a superconductor, by invoking the interfacial spin Hall effect therein. We then show that a vortex liquid in superconductors can serve as a spin-transport channel between two magnetic insulators by encoding spin information in the vorticity. The vortex-mediated nonlocal signal between the two magnetic insulators is shown to decay algebraically as a function of their separation, contrasting with the exponential decay of the quasiparticle-mediated spin transport. We envision that hydrodynamics of topological excitations, such as vortices in superconductors and domain walls in magnets, may serve as a universal framework to discuss long-range transport properties of ordered materials.

[3]
Title: Concurrent transitions in wear rate and surface microstructure in nanocrystalline Ni-W
Subjects: Materials Science (cond-mat.mtrl-sci)

Nanocrystalline metals are promising materials for wear-resistant applications due to their superior strength and hardness, but prior work has shown that cyclic loading can lead to coarsening. In this study, scratch wear tests were carried out on nanocrystalline Ni-19 at.% W films with an as-deposited grain size of 3 nm, with systematic characterization performed after different wear cycles. A new gradient nanograined microstructure is observed and a direct connection between wear rate and subsurface microstructure is discovered. A second Ni-W specimen with the same composition and a 45 nm average grain size is produced by annealing the original specimen. Subsequent wear testing shows that an identical subsurface microstructure is produced in this sample, emphasizing the importance of the cross-over in deformation mechanisms for determining the steady-state grain size during wear.

[4]
Title: Pronounced grain boundary network evolution in nanocrystalline Cu subjected to large cyclic strains
Subjects: Materials Science (cond-mat.mtrl-sci)

The grain boundary network of nanocrystalline Cu foils was modified by the systematic application of cyclic loadings and elevated temperatures having a range of magnitudes. Most broadly, the changes to the boundary network were directly correlated to the applied temperature and accumulated strain, including a 300% increase in the twin length fraction. By independently varying each treatment variable, a matrix of grain boundary statistics was built to check the plausibility of hypothesized mechanisms against their expected temperature and stress/strain dependences. These comparisons allow the field of candidate mechanisms to be significantly narrowed. Most importantly, the effect of temperature and strain on twin length fraction were found to be strongly synergistic, with the combined effect being ~150% that of the summed individual contributions. Looking beyond scalar metrics, an analysis of the grain boundary network showed that twin related domain formation favored larger sizes and repeated twin variant selection over the creation of many small domains with diverse variants. Taken together, the evidence indicates that shear-coupled boundary migration twinning is the most likely explanation for grain boundary engineering in nanocrystalline Cu.

[5]
Title: Heat transport in pristine and polycrystalline single-layer hexagonal boron nitride
Comments: 12 pages, 9 figures, 2 tables
Subjects: Materials Science (cond-mat.mtrl-sci)

We use a phase field crystal model to generate realistic large-scale bicrystalline and polycrystalline single-layer hexagonal boron nitride (h-BN) samples and employ molecular dynamics (MD) simulations with the Tersoff many-body potential to study their heat transport properties. The Kapitza thermal resistance across individual h-BN grain boundaries is calculated using the inhomogeneous nonequilibrium MD method. The resistance displays strong dependence on the tilt angle, the line tension and the defect density of the grain boundaries. We also calculate the thermal conductivity of pristine h-BN and polycrystalline h-BN with different grain sizes using an efficient homogeneous nonequilibrium MD method. The in-plane and the out-of-plane (flexural) phonons exhibit different grain size scaling of the thermal conductivity in polycrystalline h-BN and the extracted Kapitza conductance is close to that of large-tilt-angle grain boundaries in bicrystals.

[6]
Title: i-Caloric Effects: a proposal for normalization
Subjects: Materials Science (cond-mat.mtrl-sci)

Solid-state cooling based on i-caloric effects is considered the most promising alternative to replace the conventional vapor-compression refrigeration systems. It is possible to define an i-caloric effect as a thermal response registered in a material upon the application of an external field, characterized by an adiabatic temperature change ({\Delta}T_S) or an isothermal entropy change ({\Delta}S_T). Depending on the nature of the external field (magnetic field, electric field or stress field), the i-caloric effects can be categorized as magnetocaloric effect, electrocaloric effect, and mechanocaloric effect. We can still subdivide mechanocaloric effect in: elastocaloric effect, driven by uniaxial stress; barocaloric effect, driven by isotropic stress (pressure); and torsiocaloric effect, driven by a torque in a prismatic bar, causing a pure shear stress of torsion. The study of i-caloric effects dates from the beginning of 19th century. Nevertheless, due to the independent development of investigations on each effect, there are no stablished standards regarding terminology or results evaluation up to now, making the understanding quite challenging for the community. In this context, we present a proposal for normalization of i-caloric effects, considering different aspects, such as nomenclature, thermodynamics and figures of merit.

[7]
Title: Magnetic field dependence of antiferromagnetic resonance in NiO
Journal-ref: Appl. Phys. Lett. 112, 252404 (2018)
Subjects: Materials Science (cond-mat.mtrl-sci)

We report on measurements of magnetic field and temperature dependence of antiferromagnetic resonances in the prototypical antiferromagnet NiO. The frequencies of the magnetic resonances in the vicinity of 1 THz have been determined in the time-domain via time-resolved Faraday measurements after selective excitation by narrow-band superradiant terahertz (THz) pulses at temperatures down to 3K and in magnetic fields up to 10 T. The measurements reveal two antiferromagnetic resonance modes, which can be distinguished by their characteristic magnetic field dependencies. The nature of the two modes is discussed by comparison to an eight-sublattice antiferromagnetic model, which includes superexchange between the next-nearest-neighbor Ni spins, magnetic dipolar interactions, cubic magneto-crystalline anisotropy, and Zeeman interaction with the external magnetic field. Our study indicates that a two-sublattice model is insufficient for the description of spin dynamics in NiO, while the magnetic-dipolar interactions and magneto-crystalline anisotropy play important roles.

[8]
Title: Strong-coupling perturbative study of the disordered Hubbard model on honeycomb lattice
Subjects: Strongly Correlated Electrons (cond-mat.str-el); Disordered Systems and Neural Networks (cond-mat.dis-nn); Materials Science (cond-mat.mtrl-sci)

We study the Anderson disordered Hubbard model on the honeycomb lattice. The Hubbard term is han- dled with strong-coupling perturbation theory which encodes the Mott transition physics into a rich dynamical structure of a local self-energy. The local nature of self-energy allows us to combine it with kernel polynomial method and transfer matrix methods. The locality of self-energy combined with the analytic nature of the strong- coupling perturbation theory enables us to study lattices with millions of sites. The transfer matrix method in the ribbon geometry is essentially free from finite size errors and allows us to perform a careful finite size scaling of the width of the ribbon. This finite size scaling enables us to rule out the possibility of metallic phase in between the Mott and Anderson insulating phases. We therefore find a direct transition between Anderson and Mott insulators when the disorder strength W is comparable to the Hubbard interaction U . For a fixed disorder W , we obtain an interaction dependent nonmonotonic behavior of the localization length which reflects interac- tion induced enhancement of the localization length for weak and intermediate interaction strengths. Eventually at strong interactions U, the Mott localization takes over and the localization length becomes comparable to the lattice scale. This is reminiscent of the holographic determination of the Mott state where the system at IR recognizes its UV lattice scale.

[9]
Title: Tunable disorder and localization in the rare-earth nickelates
Subjects: Materials Science (cond-mat.mtrl-sci); Strongly Correlated Electrons (cond-mat.str-el)

The rare-earth nickelates are a rich playground for transport properties, known to host non-Fermi liquid character, resistance saturation and metal-insulator transitions. We report a study of transport in LaNiO3 in the presence of tunable disorder induced by irradiation. While pristine LaNiO3 samples are metallic, highly irradiated samples show insulating behaviour at all temperatures. Using irradiation fluence as a tuning handle, we uncover an intermediate region hosting a metal-insulator transition. This transition falls within the Mott-Ioffe-Regel regime wherein the mean free path is comparable to lattice spacing. In the high temperature metallic regime, we find a transition from non-Fermi liquid to a Fermi-liquid-like character. On the insulating side of the metal-insulator transition, we find behaviour that is consistent with weak localization. This is reflected in magnetoresistance that scales with the square of the field and in resistivity. In the highly irradiated insulating samples, we find good agreement with variable range hopping, consistent with Anderson localization. We find qualitatively similar behaviour in thick PrNiO3 films as well. Our results demonstrate that ion irradiation can be used to tailor transport, serving as an excellent tool to study the physics of localization.

[10]
Title: Data-driven studies of magnetic two-dimensional materials
Subjects: Materials Science (cond-mat.mtrl-sci)

We use a data-driven approach to study the magnetic and thermodynamic properties of van der Waals (vdW) layered materials. We investigate monolayers of the form A$_2$B$_2$X$_6$, based on the known material Cr$_2$Ge$_2$Te$_6$, using density functional theory (DFT) calculations and machine learning methods to determine their magnetic properties, such as magnetic order and magnetic moment. We also examine formation energies and use them as a proxy for chemical stability. We show that machine learning tools, combined with DFT calculations, can provide a computationally efficient means to predict properties of such two-dimensional (2D) magnetic materials. Our data analytics approach provides insights into the microscopic origins of magnetic ordering in these systems. For instance, we find that the X site strongly affects the magnetic coupling between neighboring A sites, which drives the magnetic ordering. Our approach opens new ways for rapid discovery of chemically stable vdW materials that exhibit magnetic behavior.

[11]
Title: Ballistic reversible gates matched to bit storage: Plans for an efficient CNOT gate using fluxons
Comments: Submitted for Reversible Computation Conference, 2018. Conference proceedings will be published by Springer as a Lecture Notes in Computer Science (LNCS). 17 pages, 6 figures
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

New computing technologies are being sought near the end of CMOS transistor scaling, meanwhile superconducting digital, i.e., single-flux quantum (SFQ), logic allows incredibly efficient gates which are relevant to the impending transition. In this work we present a proposed reversible logic, including gate simulations and schematics under the name of Reversible Fluxon Logic (RFL). In the widest sense it is related to SFQ-logic, however it relies on (some approximately) reversible gate dynamics and promises higher efficiency than conventional SFQ which is logically irreversible. Our gates use fluxons, a type of SFQ which has topological-particle characteristics in an undamped Long Josephson junction (LJJ). The collective dynamics of the component Josephson junctions (JJs) enable ballistic fluxon motion within LJJs as well as good energy preservation of the fluxon for JJ-circuit gates. For state changes, the gates induce switching of fluxon polarity during resonant scattering at an interface between different LJJs. Related to the ballistic nature of fluxons in LJJ, the gates are powered, almost ideally, only by data fluxon momentum in stark contrast to conventionally damped logic gates which are powered continuously with a bias. At first the fundamental Identity and NOT gates are introduced. Then 2-bit gates are discussed, including the IDSN gate which actually allows low fluxon-number inputs for more than 4 input states. A digital CNOT, an important milestone for 2-bit reversible superconducting gates, is planned as a central result. It uses a store and launch gate to stop and then later route a fluxon. This use of the store and launch gate allows a clocked CNOT gate and synchronization within. The digital CNOT gate could enable high efficiency relative to conventional irreversible gates and shows the utility of the IDSN as a reversible gate primitive.

[12]
Title: Coincident onset of charge density wave order at a quantum critical point in underdoped YBCO
Journal-ref: Phys. Rev. B 97, 224513 (2018)
Subjects: Superconductivity (cond-mat.supr-con)

The recently demonstrated x-ray scattering approach using a free electron laser with a high field pulsed magnet has opened new opportunities to explore the charge density wave (CDW) order in cuprate high temperature superconductors. Using this approach, we substantially degrade the superconductivity with magnetic fields up to 33 T to investigate the onset of CDW order in YBa$_2$Cu$_3$O$_x$ at low temperatures near a putative quantum critical point (QCP) at $p_1\sim$ 0.08 holes per Cu. We find no CDW can be detected in a sample with a doping concentration less than $p_1$. Our results indicate that the onset of the CDW ground state lies inside the zero-field superconducting dome, and broken translational symmetry is associated with the putative QCP at $p_1$

[13]
Title: Phase Diagrams of Multicomponent Lipid Vesicles: Effects of Spherical Topology and Finite Size
Subjects: Soft Condensed Matter (cond-mat.soft)

We study the phase behavior of multicomponent lipid bilayer vesicles that can exhibit intriguing morphological patterns and lateral phase separation. We use a modified Landau-Ginzburg model capable of describing spatially uniform phases, microemulsions, and modulated phases on a spherical surface. We calculate its phase diagram for multiple vesicle sizes using analytical and numerical techniques as well as Monte Carlo simulations. Consistent with previous studies on planar systems, we find that thermal fluctuations move phase boundaries, stabilizing phases of higher disorder. We also show that the phase diagram is sensitive to the size of the system at small vesicle radii. Such finite size effects are likely relevant in experiments on small, unilamellar vesicles and should be considered in their comparison to theoretical and simulation results.

[14]
Title: Realizing robust large-gap quantum spin Hall state in 2D HgTe monolayer on insulating substrate
Subjects: Materials Science (cond-mat.mtrl-sci)

Although many possible two-dimensional (2D) topological insulators (TIs) have been predicted in recent years, there is still lack of experimentally realizable 2D TI. Through first-principles and tight-binding simulations, we found an effective way to stabilize the robust quantum spin Hall state with a large nontrivial gap of 227 meV in 2D honeycomb HgTe monolayer by the Al$_2$O$_3$(0001) substrate. The band topology originates from the band inversion between the $s-$like and $p-$like orbitals that are contributed completely by the Hg and Te atoms, so the quantized edge states are restricted within the honeycomb HgTe monolayer. Meanwhile, the strong interaction between HgTe and Al$_2$O$_3$(0001) ensures high stability of the atomic structure. Therefore, the TI states may be realized in HgTe/Al$_2$O$_3$(0001) at high temperature.

[15]
Title: Spin triplet superconducting proximity effect in a ferromagnetic semiconductor
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

Conventional spin-singlet superconductivity that deeply penetrates into ferromagnets is typically killed by the exchange interaction, which destroys the spin-singlet pairs. Under certain circumstances, however, superconductivity survives this interaction by adopting the pairing behavior of spin triplets. The necessary conditions for the emergence of triplet pairs are well-understood, owing to significant developments in theoretical frameworks and experiments. The long-term challenges to inducing superconductivity in magnetic semiconductors, however, involve difficulties in observing the finite supercurrent, even though the generation of superconductivity in host materials has been well-established and extensively examined. Here, we show the first evidence of proximity-induced superconductivity in a ferromagnetic semiconductor (In, Fe)As. The supercurrent reached a distance scale of $\sim 1~\mu$m, which is comparable to the proximity range in two-dimensional electrons at surfaces of pure InAs. Given the long range of its proximity effects and its response to magnetic fields, we conclude that spin-triplet pairing is dominant in proximity superconductivity. Therefore, this progress in ferromagnetic semiconductors is a breakthrough in semiconductor physics involving unconventional superconducting pairing.

[16]
Title: Electronic structures of iMAX phases and their two-dimensional derivatives: A family of piezoelectric materials
Journal-ref: Physical Review Materials (2018)
Subjects: Materials Science (cond-mat.mtrl-sci)

Recently, a group of MAX phases, (Mo$_{2/3}$Y$_{1/3}$)$_2$AlC, (Mo$_{2/3}$Sc$_{1/3}$)$_2$AlC, (W$_{2/3}$Sc$_{1/3}$)$_2$AlC, (W$_{2/3}$Y$_{1/3}$)$_2$AlC, and (V$_{2/3}$Zr$_{1/3}$)$_2$AlC, with in-plane ordered double transition metals, named iMAX phases, have been synthesized. Experimentally, some of these MAX phases can be chemically exfoliated into two-dimensional (2D) single- or multilayered transition metal carbides, so-called MXenes. Accordingly, the 2D nanostructures derived from iMAX phases are named iMXenes. Here, we investigate the structural stabilities and electronic structures of the experimentally discovered iMAX phases and their possible iMXene derivatives. We show that the iMAX phases and their pristine, F, or OH-terminated iMXenes are metallic. However, upon O termination, (Mo$_{2/3}$Y$_{1/3}$)$_2$C, (Mo$_{2/3}$Sc$_{1/3}$)$_2$C, (W$_{2/3}$Y$_{1/3}$)$_2$C, and (W$_{2/3}$Sc$_{1/3}$)$_2$C iMXenes turn into semiconductors. Owing to the absence of centrosymmetry, the semiconducting iMXenes may find applications in piezoelectricity. Our calculations reveal that the semiconducting iMXenes possess giant piezoelectric coefficients as large as 45$\times10^{-10}$~C/m.

[17]
Title: Semantic information, agency, and nonequilibrium statistical physics
Subjects: Statistical Mechanics (cond-mat.stat-mech)

Information theory provides various measures of correlations holding between the states of two systems, which are sometimes called measures of "syntactic information". At the same time, the concept of "semantic information" refers to information which is in some sense meaningful rather than merely correlational. Semantic information plays an important role in many fields -- including biology, cognitive science, artificial intelligence -- and there has been a long-standing interest in a quantitative theory of semantic information. In this work, we introduce such a theory, which defines semantic information as the syntactic information that a physical system has about its environment that is causally necessary for the system to maintain its own existence. We operationalize self-maintenance in terms of the ability of the system to maintain a low entropy state, which we use to make connections to results in nonequilibrium statistical physics. Our approach leads naturally to formal definitions of notions like "value of information", "semantic content", and "agency". Our approach is grounded purely in the intrinsic dynamics of a system coupled to some environment, and is applicable to any physical system.

[18]
Title: Reconstructing Entanglement Hamiltonian via Entanglement Eigenstates
Subjects: Strongly Correlated Electrons (cond-mat.str-el); Other Condensed Matter (cond-mat.other); Quantum Physics (quant-ph)

The entanglement Hamiltonian $H_E$, defined through the reduced density matrix of a subsystem $\rho_A=\exp(-H_E)$, is an important concept in understanding the nature of quantum entanglement in many-body systems and quantum field theories. In this work, we explore a numerical scheme which explicitly reconstructs the entanglement Hamiltonian using one entangled mode (i.e., an eigenstate) of $\rho_A$. We demonstrate and benchmark this scheme on quantum spin lattice models. The resulting $H_E$ bears a form similar to a physical Hamiltonian with spatially varying couplings, which allows us to make quantitative comparison with perturbation theory and conformal field theory.

[19]
Title: Monolayer Mg$_{2}$C: Negative Poisson's ratio and unconventional 2D emergent fermions
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

Novel two-dimensional (2D) emergent fermions and negative Poisson's ratio in 2D materials are fascinating subjects of research. Here, based on first-principles calculations and theoretical analysis, we predict that the hexacoordinated Mg$_{2}$C monolayer hosts both exotic properties. We analyze its phonon spectrum, reveal the Raman active modes, and show that it has small in-plane stiffness constants. Particularly, under the tensile strain in the zigzag direction, the Mg$_{2}$C monolayer shows an intrinsic negative Poisson's ratio $\sim -0.023$, stemming from its unique puckered hinge structure. The material is metallic at its equilibrium state. A moderate biaxial strain can induce a metal-semimetal-semiconductor phase transition, during which several novel types of 2D fermions emerge, including the anisotropic Dirac fermions around 12 tilted Dirac points in the metallic phase, the $2$D double Weyl fermions in the semimetal phase where the conduction and valence bands touch quadratically at a single Fermi point, and the 2D pseudospin-1 fermions at the critical point of the semimetal-semiconductor phase transition where three bands cross at a single point on the Fermi level. In addition, uniaxial strains along the high-symmetry directions break the three-fold rotational symmetry and reduce the number of Dirac points. Interestingly, it also generates 2D type-II Dirac points. We construct effective models to characterize the properties of these novel fermions. Our result reveals Mg$_{2}$C monolayer as an intriguing platform for the study of novel 2D fermions, and also suggests its great potential for nanoscale device applications.

[20]
Title: Discommensuration-enhanced superconductivity in the charge density wave phases of transition-metal dichalcogenides
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Statistical Mechanics (cond-mat.stat-mech); Superconductivity (cond-mat.supr-con)

We introduce a McMillan-Ginzburg-Landau theory to describe the cooperative coexistence of charge-density and superconducting order in two-dimensional crystals. With a free-energy that explicitly accounts for the competition between commensurate and incommensurate ground states, we are able to map the transition between these phases and monitor the development of discommensurations in the near-commensurate regime. Attributing the enhancement of superconducting order to density-wave fluctuations, we propose a coupling scheme that yields a phase diagram in qualitative agreement with experiments in conducting transition metal dichalcogenides. The model predicts the development of non-uniform superconductivity similar to that arising from a pair-density wave, except that the spatial texture is driven by the underlying density modulation.

[21]
Title: Percolation Thresholds and Fisher Exponents in Hypercubic Lattices
Subjects: Statistical Mechanics (cond-mat.stat-mech)

We use invasion percolation to compute highly-accurate numerical values for bond and site percolation thresholds p_c on the hypercubic lattice Z^d for d = 4,...,13. We also compute the Fisher exponent tau governing the cluster size distribution at criticality. Our results support the claim that d=6 is the upper critical dimension for percolation, with logarithmic corrections to power-law scaling at d=6.

[22]
Title: Raman spectra of nanoparticles: elasticity theory-like approach for optical phonons
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

A simple way to investigate theoretically the Raman spectra (RS) of nonpolar nanoparticles is proposed. For this aim we substitute the original lattice optical phonon eigenproblem by the continuous Klein-Fock-Gordon-like equation with Dirichlet boundary conditions. This approach provides the basis for the continuous description of optical phonons in the same manner how the elasticity theory describes the longwavelength acoustic phonons. Together with continuous reformulation of the bond polarization model it allows to calculate the RS of nanoparticles without referring to their atomistic structure. It ensures the powerful tool for interpreting the experimental data, studying the effects of particle shape and their size distribution. We successfully fit recent experimental data on very small diamond and silicon particles, for which the commonly used phonon confinement model fails. The predictions of our theory are compared with recent results obtained within the dynamical matrix method - bond polarization model (DMM-BPM) approach and an excellent agreement between them is found. The advantages of the present theory are its simplicity and the rapidity of calculations. We analyze how the RS are affected by the nanoparticle faceting and propose a simple power law for Raman peak position dependence on the facets number. The method of powder RS calculations is formulated and the limitations on the accuracy of our analysis are discussed.

[23]
Title: Chirality Josephson current due to a novel quantum anomaly in inversion-asymmetric Weyl semimetals
Subjects: Superconductivity (cond-mat.supr-con); High Energy Physics - Theory (hep-th)

We study Josephson junctions based on inversion-asymmetric Weyl semimetals under the influence of Zeeman fields. We show that, due to distinct spin textures, the Weyl nodes of opposite chiralities respond differently to a Zeeman field in a particular direction. Remarkably, a Zeeman field perpendicular to the junction modulates the phase in the current-phase relation (CPR) of opposite chiralities differently, leading to the striking phenomenon of a finite chirality Josephson current existing even in the absence of a phase difference across the junction. This phenomenon can be understood as a novel type of quantum anomaly at low energies. We predict that, the chirality-dependent CPR and hence the chirality Josephson current can be detected experimentally by an anomalous Fraunhofer pattern which is insensitive to chemical potentials, junction length, and (low) temperature.

[24]
Title: The structure of near stoichiometric Ge-Ga-Sb-S glasses: a reverse Monte Carlo study
Comments: 23 pages, 5 figures, submitted to Journal of Non-crystalline Solids
Subjects: Materials Science (cond-mat.mtrl-sci); Disordered Systems and Neural Networks (cond-mat.dis-nn); Chemical Physics (physics.chem-ph)

The structure of Ge$_{22}$Ga$_3$Sb$_{10}$S$_{65}$ and Ge$_{15}$Ga$_{10}$Sb$_{10}$S$_{65}$ glasses was investigated by neutron diffraction (ND), X-ray diffraction (XRD), and extended X-ray absorption fine structure (EXAFS) measurements at the Ge, Ga and Sb K-edges. Experimental data sets were fitted simultaneously in the framework of the reverse Monte Carlo (RMC) simulation technique. Short range order parameters were determined from the obtained large-scale configurations. It was found that the coordination numbers of Ge, Sb and S are around the values predicted by the Mott-rule (4, 3 and 2, respectively). The Ga atoms have on average 4 nearest neighbors. The structure of these stoichiometric glasses can be described by the chemically ordered network model: Ge-S, Ga-S and Sb-S bonds are the most important. A distortion of Ge(Ga)S$_{4/2}$ and/or SbS$_{3/2}$ units can be observed in the form of long Ge(Ga)-S and/or Sb-S distances (0.3 - 0.4 {\AA} higher than the usual covalent bond lengths).

[25]
Title: Two-dimensional, blue phase tactoids
Comments: 13 pages, 5 figures, Molecular Physics, Frenkel Special Issue (2018)
Subjects: Soft Condensed Matter (cond-mat.soft)

We use full nematohydrodynamic simulations to study the statics and dynamics of monolayers of cholesteric liquid crystals. Using chirality and temperature as control parameters we show that we can recover the two-dimensional blue phases recently observed in chiral nematics, where hexagonal lattices of half-skyrmion topological excitations are interleaved by lattices of trefoil topological defects. Furthermore, we characterise the transient dynamics during the quench from isotropic to blue phase. We then proceed by confining cholesteric stripes and blue phases within finite-sized tactoids and show that it is possible to access a wealth of reconfigurable droplet shapes including disk-like, elongated, and star-shaped morphologies. Our results demonstrate a potential for constructing controllable, stable structures of liquid crystals by constraining 2D blue phases and varying the chirality, surface tension and elastic constants.

[26]
Title: Applications for ultimate spatial resolution in LASER based $μ$-ARPES: A FeSe case study
Subjects: Materials Science (cond-mat.mtrl-sci)

Combining Angle resolved photoelectron spectroscopy (ARPES) and a $\mu$-focused Laser, we have performed scanning ARPES microscopy measurements of the domain population within the nematic phase of FeSe single crystals. We are able to demonstrate a variation of the domain population density on a scale of a few 10 $\mu$m while constraining the upper limit of the single domain size to less than 5 $\mu m$. This experiment serves as a demonstration of how combining the advantages of high resolution Laser ARPES and an ultimate control over the spatial dimension can improve investigations of materials by reducing the cross contamination of spectral features of different domains.

[27]
Title: Extremely large magnetoresistance and the complete determination of the Fermi surface topology in the semimetal ScSb
Subjects: Materials Science (cond-mat.mtrl-sci)

We report the magnetoresistance of ScSb, which is a semimetal with a simple rocksalt-type structure. We found that the magnetoresistance reaches $\sim$28000 % at 2 K and 14 T in our best sample, and it exhibits a resistivity plateau at low temperatures. The Shubnikov-de Haas oscillations extracted from the magnetoresistance data allow the full construction of the Fermi surface, including the so-called $\alpha_3$ pocket which has been missing in other closely related monoantimonides, and an additional hole pocket centered at $\Gamma$. The electron concentration ($n$) and the hole concentration ($p$) are extracted from our analysis, which indicate that ScSb is a nearly compensated semimetal with $n/p\approx0.93$. The calculated band structure indicates the absence of a band inversion, and the large magnetoresistance in ScSb can be attributed to the nearly perfect compensation of electrons and holes, despite the existence of the additional hole pocket.

[28]
Title: Tunneling-induced restoration of classical degeneracy in quantum kagome ice
Subjects: Strongly Correlated Electrons (cond-mat.str-el)

Quantum effect is expected to dictate the behaviour of physical systems at low temperature. For quantum magnets with geometrical frustration, quantum fluctuation lifts the macroscopic classical degeneracy, and exotic quantum states emerge. However, how different types of quantum processes entangle wave functions in a constrained Hilbert space is not well understood. Here, we study the topological entanglement entropy the thermal entropy of a quantum ice model on a geometrically frustrated kagome lattice. We find that the system does not show a $Z_2$ topological order down to extremely low temperatures, yet continues to behave like a classical kagome ice with finite residual entropy. Our theoretical analysis indicates that an intricate competition of off-diagonal and diagonal quantum tunneling processes leading to a suppression of the quantum energy scale. This new paradigm suggests quantum spin ice materials can be engineered to study the novel quantum-classical transition.

[29]
Title: Nano-structured thin films growth in stochastic plasma-condensate systems
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

We derive the stochastic model of plasma-condensate systems by taking into account anisotropy in transference of adatoms between neighbor layers and by introducing fluctuations of adsorbate flux. We show, that by varying the fluctuation's intensity on can govern dynamics of pattern formation on intermediate layer of multi-layer plasma-condensate system. It is shown that the morphology of the growing surface, type of surface structures and their linear size can be controlled by the intensity of the adsorbate flux fluctuations.

[30]
Title: Lattice dynamics of the cluster chain compounds M2Mo6Se6
Comments: 10 pages including appendix with raw data plots etc. accepted in Phys. Rev. B
Journal-ref: Phys. Rev. B (2018)
Subjects: Superconductivity (cond-mat.supr-con)

The lattice dynamics of members of the M2Mo6Se6 family of materials with guest ions M = K, Rb, Cs, In, and Tl has been studied using inelastic x-ray scattering and Raman spectroscopy at room temperature, as well as by ab-initio calculations. We find a good match between calculations and experiment, both for structure factors (Eigenvectors) and for the calculated phonon frequencies. The observed lattice dynamics for Tl2Mo6Se6 show no signs of anharmonicity or absence of avoided dispersion crossings, thus ruling out previously hypothesised rattling phonon modes. The reduced mode energies for In2Mo6Se6 are identified as only partially responsible for the lower superconducting transition temperature Tc in this material when compared to Tl2Mo6Se6.

[31]
Title: Nuclear spin-lattice relaxation time in TaP and the Knight shift of Weyl semimetals
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Strongly Correlated Electrons (cond-mat.str-el)

We first analyze the recent experimental data on the nuclear spin-lattice relaxation rate of the Weyl semimetal TaP. We argue that its non-monotonic temperature dependence is explained by the temperature dependent chemical potential of Weyl fermions. We also develop the theory of the Knight shift in Weyl semimetals, which contains two counteracting terms. The diamagnetic term follows $-\ln[W/\max(|\mu|,k_BT)]$ with $W$, $\mu$ and $T$ being the high energy cutoff, chemical potential and temperature, respectively, and is always negative. The paramagnetic term scales with $\mu$ and changes sign depending on the doping level. Altogether, the Knight shift is predicted to vanish or even change sign upon changing the doping or the temperature, making it a sensitive tool to identify Weyl points. We also calculate the Korringa relation for Weyl semimetals which shows an unusual energy dependence rather than being constant as expected for a non-interacting Fermi system.

[32]
Title: Unconventional critical state in YBa$_{2}$Cu$_{3}$O$_{7-δ}$ thin films with a vortex-pin lattice fabricated by masked He$^+$ ion beam irradiation
Journal-ref: Superconductor Science and Technology 31 (2018) 044002
Subjects: Superconductivity (cond-mat.supr-con); Materials Science (cond-mat.mtrl-sci)

Thin superconducting YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ films are patterned with a vortex-pin lattice consisting of columnar defect regions (CDs) with 180 nm diameter and 300 nm spacing. They are fabricated by irradiation with 75 keV He$^+$ ions through a stencil mask. Peaks of the critical current reveal the commensurate trapping of vortices in domains near the edges of the sample. Upon ramping an external magnetic field, the positions of the critical current peaks are shifted from their equilibrium values to lower magnetic fields in virgin and to higher fields in field-saturated down-sweep curves, respectively. Based on previous theoretical predictions, this irreversibility is interpreted as a nonuniform, terrace-like critical state, in which individual domains are occupied by a constant number of vortices per pinning site. The magnetoresistance, probed at low current densities, is hysteretic and angle dependent and exhibits minima that correspond to the peaks of the critical current. The minima's positions scale with the component of the magnetic field parallel to the axes of the CDs, as long as the tilted vortices can be accommodated within the CDs. This behavior, different from unirradiated films, confirms that the CDs dominate the pinning.

[33]
Title: Measuring the single-particle density matrix for fermions and hard-core bosons in an optical lattice
Subjects: Quantum Gases (cond-mat.quant-gas); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Quantum Physics (quant-ph)

Ultracold atoms in optical lattices provide clean, tunable, and well-isolated realizations of paradigmatic quantum lattice models. With the recent advent of quantum-gas microscopes, they now also offer the possibility to measure the occupations of individual lattice sites. What, however, has not yet been achieved is to measure those elements of the single-particle density matrix, which are off-diagonal in the occupation basis. Here, we propose a scheme to access these basic quantities both for fermions as well as hard-core bosons and investigate its accuracy and feasibility. The scheme relies on the engineering of a large effective tunnel coupling between distant lattice sites and a protocol that is based on measuring site occupations after two subsequent quenches.

[34]
Title: Three-dimensional stability of leapfrogging quantum vortex rings
Authors: Victor P. Ruban
Subjects: Other Condensed Matter (cond-mat.other); Pattern Formation and Solitons (nlin.PS)

It is shown by numerical simulations within a regularized Biot-Savart law that dynamical systems of two or three leapfrogging coaxial quantum vortex rings having a core width $\xi$ and initially placed near a torus of radii $R_0$ and $r_0$, can be three-dimensionally (quasi-)stable in some regions of parameters $\Lambda=\log(R_0/\xi)$ and $W=r_0/R_0$. At fixed $\Lambda$, stable bands on $W$ are intervals between non-overlapping main parametric resonances for different (integer) azimuthal wave numbers $m$. The stable intervals are most wide ($\Delta W\sim 0.01...0.04$) between $m$-pairs $(1,2)$ and $(2,3)$ at $\Lambda\approx 4...8$ thus corresponding to micro/mesoscopic sizes of vortex rings in the case of superfluid $^4$He. With four and more rings, at least for $W>0.1$, resonances overlap for all $\Lambda$ and no stable domains exist.

[35]
Title: Spin, orbital, Weyl and other glasses in topological superfluids
Comments: 20 pages, 6 figures, prepared for QFS-2018, Tokyo
Subjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Other Condensed Matter (cond-mat.other)

One of the most spectacular discoveries made in superfluid $^3$He confined in a nanostructured material like aerogel or nafen was the observation of the destruction of the long-range orientational order by a weak random anisotropy. The quenched random anisotropy provided by the confining material strands produces several different glass states resolved in NMR experiments in the chiral superfluid $^3$He-A and in the time-reversal-invariant polar phase. The smooth textures of spin and orbital order parameters in these glasses can be characterized in terms of the randomly distributed topological charges, which describe skyrmions, spin vortices and hopfions. In addition, in these skyrmion glasses the momentum-space topological invariants are randomly distributed in space. The Chern mosaic, Weyl glass, torsion glass and other exotic topological sates are examples of close connections between the real-space and momentum-space topologies in superfluid $^3$He phases in aerogel.

[36]
Title: Quantum nonlinear phononics route towards nonequilibrium materials engineering: Melting dynamics of a ferrielectric charge density wave
Subjects: Strongly Correlated Electrons (cond-mat.str-el)

Negative nonlinear electron-phonon coupling involving an infrared-active phonon mode can lead to an instability towards the formation of a polar lattice distortion with ferrielectric (FE) moments accompanied by an electronic charge-density wave (CDW). Analyzing a small model system in and out of thermal equilibrium, we investigate the FE-CDW and its melting dynamics following an ultrashort laser pulse that drives the ionic dipoles. We observe nonequilibrium coherent phonon amplitude mode oscillations that soften towards the transition to the normal phase. Our case study serves as a first step towards a microscopic understanding of quantum nonlinear phononics as a basis for nonequilibrium control in quantum materials.

[37]
Title: Dynamically Generated Synthetic Electric Fields for Photons
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Quantum Physics (quant-ph)

Static synthetic magnetic fields give rise to phenomena including the Lorentz force and the quantum Hall effect even for neutral particles, and they have by now been implemented in a variety of physical systems. Moving towards fully dynamical synthetic gauge fields allows, in addition, for backaction of the particles' motion onto the field. If this results in a time-dependent vector potential, conventional electromagnetism predicts the generation of an electric field. Here, we show how synthetic electric fields for photons arise self-consistently due to the nonlinear dynamics in a driven system. Our analysis is based on optomechanical arrays, where dynamical gauge fields arise naturally from phonon-assisted photon tunneling. We study open, one-dimensional arrays, where synthetic magnetic fields are absent. However, we show that synthetic electric fields can be generated dynamically, which, importantly, suppress photon transport in the array. The generation of these fields depends on the direction of photon propagation, leading to a novel mechanism for a photon diode, inducing nonlinear nonreciprocal transport via dynamical synthetic gauge fields.

[38]
Title: Electron-phonon properties and superconductivity of doped antimonene
Subjects: Superconductivity (cond-mat.supr-con); Materials Science (cond-mat.mtrl-sci)

Antimonene is a recently discovered two-dimensional semiconductor with exceptional environmental stability, high carrier mobility, and strong spin-orbit interactions. In combination with electric field, the latter provides an additional degree of control over the materials' properties because of induced spin splitting. Here, we report on a computational study of electron-phonon coupling and superconductivity in $n$- and $p$-doped antimonene, where we pay a special attention on the effect of the perpendicular electric field. We find that at realistic carrier concentrations, antimonene can be turned into a state with strong electron-phonon coupling, with the mass enhancement factor $\lambda$ of up to five. In this regime, antimonene is expected to be a superconductor with the critical temperature of $\sim$17 K. Application of bias voltage leads to a considerable modification of the electronic structure, affecting the electron-phonon coupling in antimonene. While these effects are less obvious in case of electron-doping, field-effect in hole-doped antimonene results in a considerable variation of the critical temperature depending on bias voltage.

[39]
Title: Two-dimensional spin liquid behaviour in the triangular-honeycomb antiferromagnet TbInO$_3$
Comments: 23 pages, 5 figures, supporting information
Subjects: Strongly Correlated Electrons (cond-mat.str-el)

Spin liquid ground states are predicted to arise within several distinct scenarios in condensed matter physics. The observation of these disordered magnetic states is particularly pervasive amongst a class of materials known as frustrated magnets, in which the competition between various magnetic exchange interactions prevents the system from adopting long-range magnetic order at low temperatures. Spin liquids continue to be of great interest due to their exotic nature and the possibility that they may support fractionalised excitations, such as Majorana fermions. Systems that allow for such phenomena are not only fascinating from a fundamental perspective but may also be practically significant in future technologies based on quantum computation. Here we show that the underlying antiferromagnetic sublattice in TbInO$_3$ undergoes a crystal field induced triangular-to-honeycomb dilution at low temperatures. The absence of a conventional magnetic ordering transition at the lowest measurable temperatures indicates that another critical mechanism must govern in the ground state selection of TbInO$_3$. We propose that anisotropic exchange interactions, mediated through strong spin-orbit coupling on the emergent honeycomb lattice of TbInO$_3$, give rise to a highly frustrated spin liquid.

[40]
Title: Growth evolution of self-affine thermally evaporated KBr thin films: A fractal assessment
Subjects: Materials Science (cond-mat.mtrl-sci); Instrumentation and Detectors (physics.ins-det)

In this article, fractal concepts were used to explore the thermally evaporated potassium bromide thin films of different thicknesses 200, 300, and 500 nm respectively; grown on aluminium substrates at room temperature. The self-affine or self similar nature of growing surfaces was investigated by autocorrelation function and obtained results are compared with the morphological envelope method. Theoretical estimations revealed that the global surface parameters such as, interface width and lateral correlation length are monotonically decreased with increasing film thickness. Also, from height profile and A-F plots, it has been perceived that irregularity/ complexity of growing layers was significantly influenced by thickness. On the other hand, the fractal dimension and local roughness exponent, estimated by height-height correlation function, do not suggest such dependency.

[41]
Title: Quantum Transport and Band Structure Evolution under High Magnetic Field in Few-Layer Tellurene
Subjects: Materials Science (cond-mat.mtrl-sci); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

Quantum Hall effect (QHE) is a macroscopic manifestation of quantized states which only occurs in confined two-dimensional electron gas (2DEG) systems. Experimentally, QHE is hosted in high mobility 2DEG with large external magnetic field at low temperature. Two-dimensional van der Waals materials, such as graphene and black phosphorus, are considered interesting material systems to study quantum transport, because it could unveil unique host material properties due to its easy accessibility of monolayer or few-layer thin films at 2D quantum limit. Here for the first time, we report direct observation of QHE in a novel low-dimensional material system: tellurene.High-quality 2D tellurene thin films were acquired from recently reported hydrothermal method with high hole mobility of nearly 3,000 cm2/Vs at low temperatures, which allows the observation of well-developed Shubnikov-de-Haas (SdH) oscillations and QHE. A four-fold degeneracy of Landau levels in SdH oscillations and QHE was revealed. Quantum oscillations were investigated under different gate biases, tilted magnetic fields and various temperatures, and the results manifest the inherent information of the electronic structure of Te. Anomalies in both temperature-dependent oscillation amplitudes and transport characteristics were observed which are ascribed to the interplay between Zeeman effect and spin-orbit coupling as depicted by the density functional theory (DFT) calculations.

[42]
Title: Current reversal in interacting colloids under time-periodic drive
Subjects: Statistical Mechanics (cond-mat.stat-mech)

Using molecular dynamics simulations, we study particle-transport in a system of interacting colloidal particles on a ring, where the system is driven by a time-dependent external potential, moving along the ring. We consider two driving protocols: (i) the external potential barrier moves with a uniform velocity $v$ along the ring, or (ii) it moves in discrete jumps with jump-length $l$ and waiting time $\tau$ with an effective velocity $v=l/\tau$. The time-averaged (dc) particle current which always remains positive in case (i), interestingly reverses its direction in case (ii) upon tuning the particle-number density $\rho_0$ and the effective barrier velocity $v$. We also find a scaling form for the current in terms of number density, barrier velocity, barrier height and temperature of the system.

[43]
Title: Electronic properties of Bi-doped GaAs(001) semiconductors
Subjects: Materials Science (cond-mat.mtrl-sci)

Despite its potential in the fields of optoelectronics and topological insulators, experimental electronic band structure studies of Bi-doped GaAs are scarce. The reason is the complexity of growth which tends to leave bulk and in particular surface properties in an undefined state. Here we present an in depth investigation of structural and electronic properties of GaAsBi epilayers grown by molecular beam epitaxy with high (001) crystalline order and well-defined surface structures evident from low-energy electron diffraction. X-ray and ultraviolet photoemission spectrocopy as well as angle-resolved photoemission data at variable photon energies allows to disentangle a Bi-rich surface layer with $(1\times3)$ symmetry from the effects of Bi atoms incorporated in the GaAs bulk matrix. The influence of Bi concentrations up to $\approx 1$\% integrated in the GaAs bulk are visible in angle-resolved photoemission spectra after mild ion bombardment and subsequent annealing steps. Interpretation of our results is obtained via density functional theory simulations of bulk and $\beta 2(2\times 4)$ reconstructed slab geometries with and without Bi. Bi-induced energy shifts in the dispersion of GaAs heavy and light hole bulk bands are evident both in experiment and theory, which are relevant for modulations in the optical band gap and thus optoelectronic applications.

[44]
Title: Bulk and surface spin conductivity in topological insulators with hexagonal warping
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

We investigate the spin conductivity of topological insulators taking into account both the surface and quasi-two-dimensional bulk states. We apply a low-energy expansion of the Hamiltonian up to the third order in momentum and take into account the vertex corrections arising due to the short range disorder. Hexagonal warping gives rise to the additional anisotropic components in the spin conductivity tensor. Typically, isotropic part of the spin conductivity is larger than anisotropic one. The helical regime for the bulk states, in which the electrons in the Fermi level have the same projection of the spin on the direction of momentum, have been studied in a more detail. In this regime, a substantial increase of the spin conductivity contribution from the bulk states at the Fermi level is observed. We find that the bulk spin conductivity is insensitive to disorder if Rashba spin-orbit coupling is larger than disorder strength, otherwise, it is strongly suppressed. The contribution to the spin conductivity from the surface states is almost independent of the chemical potential, robust to disorder and its value is comparable to the spin conductivity contribution from the bulk states per layer. The obtained results are in agreement with experimental data.

[45]
Title: Spin-Transfer Torque Induced Paramagnetic Resonance
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

We show how the spin-transfer torque generated by an AC voltage may be used to excite a paramagnetic resonance of an atomic spin deposited on a metallic surface. This mechanism is independent of the environment of the atom and may explain the ubiquity of the paramagnetic resonance reported by S. Baumann et al. [Science 350, 417 (2015)]. The current and spin dynamics are modeled by a time-dependent Redfield master equation generalized to account for the periodic driven voltage. Our approach shows that the resonance effect is a consequence of the non-linearity of the coupling between the magnetic moment and the spin polarized current which generates a large second-harmonic amplitude that can be measured in the current signal.

[46]
Title: Application of the Onsager's variational principle to the dynamics of a solid toroidal island on a substrate
Subjects: Soft Condensed Matter (cond-mat.soft); Materials Science (cond-mat.mtrl-sci)

In this paper, we consider the capillarity-driven evolution of a solid toroidal island on a flat rigid substrate, where mass transport is controlled by surface diffusion. This problem is representative of the geometrical complexity associated with the solid-state dewetting of thin films on substrates. We apply the Onsager's variational principle to develop a general approach for describing surface diffusion-controlled problems. Based on this approach, we derive a simple, reduced-order model and obtain an analytical expression for the rate of island shrinking and validate this prediction by numerical simulations based on a full, sharp-interface model. We find that the rate of island shrinking is proportional to the material constants $B$ and the surface energy density $\gamma_0$, and is inversely proportional to the island volume $V_0$. This approach represents a general tool for modeling interface diffusion-controlled morphology evolution.

[47]
Title: Planar Hall effect in type II Dirac semimetal VAl$_{3}$
Subjects: Materials Science (cond-mat.mtrl-sci); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

The study of electronic properties in topological systems is one of the most fascinating topics in condensed matter physics, which has generated enormous interests in recent times. New materials are frequently being proposed and investigated to identify their non-trivial band structure. While sophisticated techniques such as angle-resolved photoemission spectroscopy have become popular to map the energy-momentum relation, the transport experiments lack any direct confirmation of Dirac and Weyl fermions in a system. From band structure calculations, VAl$_{3}$ has been proposed to be a type II topological Dirac semimetal. This material represents a large family of isostructural compounds, all having similar electronic band structure and is an ideal system to explore the rich physics of Lorentz symmetry violating Dirac fermions. In this work, we present a detailed analysis on the magnetotransport properties of VAl$_{3}$. A large, non-saturating magnetoresistance has been observed. Hall resistivity reveals the presence of two types of charge carriers with high mobility. Our measurements show a large planar Hall effect in this material, which is robust and can be easily detectable up to high temperature. This phenomenon originates from the relativistic chiral anomaly and non-trivial Berry curvature, which validates the theoretical prediction of the Dirac semimetal phase in VAl$_{3}$.

[48]
Title: Distribution of waiting times between electron cotunnelings
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

Single electron transport through quantum dots or molecules that are weakly coupled to macroscopic electrodes is governed by sequential processes in the resonant tunneling regime. In the Coulomb blockade regime, however, cotunneling processes dominate. Cotunneling is an inherently quantum phenomenon, and thus gives rise to interesting observations, such as in increase in the current shot noise. We consider two questions in this paper. Given that an electron has tunneled from the source to the drain via a cotunneling or sequential process, what is the waiting time until another electron cotunnels from the source to the drain? What are the statistical properties of these waiting time intervals? In answering these questions, we extend the existing formalism for waiting time distributions in single electron transport to include cotunneling processes via an n-resolved Markovian master equation. We demonstrate that for a single resonant level the waiting time distribution including cotunneling processes yields information on individual tunneling amplitudes, and that cotunneling induces small correlations in the waiting times.

[49]
Title: An Analytical Dynamical Response Theory for Bounded Medium Without Additional Boundary Conditions: A Unified Perspective of Common Models
Authors: Hai-Yao Deng
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

We derive an analytical dynamical response theory for semi-infinite materials (SIMs) without additional boundary conditions (ABCs). The theory is generic with its basic structure totally independent of the particulars of electron dynamics. Analytical expressions are then obtained of the density-density response function. It is shown that this function is naturally parsed into two parts, one of which represents primality a bulk property while the other a pure surface property. We then apply the theory to common electron dynamics models and provide a unified view of their underlying propositions. The models studied include the local dielectric model (DM), the dispersive hydrodynamic model (HDM) and specular reflection model (SRM), as well as the less common semi-classical model (SCM) based on Boltzmann's transport equation. We show that the SRM is an extension of the HDM, just as the HDM is an extension of the DM. The SCM improves over the SRM critically through the inclusion of translation symmetry breaking and surface roughness effects. We further employ the response function to evaluate the dynamical structure factor, which plays an important role in particle scattering. Expectedly, this factor reveals a peak due to the excitation of surface plasma waves (SPWs). Surprisingly, however, the peak is shown to be considerably sharper in the SCM than in other models. Its width may actually be made to vanish due to an incipient instability of the system. At the critical point, SPWs are therefore lossless. We also study the distribution of charges induced by a charged particle grazing over a SIM surface at constant speed. This distribution is shown to contain model-specific features that are of immediate experimental interest. Our work solves a fundamental problem in condensed matter physics and surface science and is expected to find broad applications.

[50]
Title: Two and three electrons on a sphere: A generalized Thomson problem
Authors: Liu Yang, Zhenwei Yao
Journal-ref: Phys. Rev. B 97, 235431, 2018
Subjects: Strongly Correlated Electrons (cond-mat.str-el); Materials Science (cond-mat.mtrl-sci)

Generalizing the classical Thomson problem to the quantum regime provides an ideal model to explore the underlying physics regarding electron correlations. In this work, we systematically investigate the combined effects of the geometry of the substrate and the symmetry of the wave function on correlations of geometrically confined electrons. By the numerical configuration interaction method in combination with analytical theory, we construct symmetrized ground-state wave functions; analyze the energetics, correlations, and collective vibration modes of the electrons; and illustrate the routine for the strongly correlated, highly localized electron states with the expansion of the sphere. This work furthers our understanding about electron correlations on confined geometries and shows the promising potential of exploiting confinement geometry to control electron states.

[51]
Title: Detection and characterization of Many-Body Localization in Central Spin Models
Subjects: Disordered Systems and Neural Networks (cond-mat.dis-nn); Quantum Physics (quant-ph)

We analyze a disordered central spin model, where a central spin interacts equally with each spin in a periodic one dimensional random-field Heisenberg chain. If the Heisenberg chain is initially in the many-body localized (MBL) phase, we find that the coupling to the central spin suffices to delocalize the chain for a substantial range of coupling strengths. We calculate the phase diagram of the model and identify the phase boundary between the MBL and ergodic phase. Within the localized phase, the central spin significantly enhances the rate of the logarithmic entanglement growth and its saturation value. We attribute the increase in entanglement entropy to a non-extensive enhancement of magnetization fluctuations induced by the central spin. Finally, we demonstrate that correlation functions of the central spin can be utilized to distinguish between MBL and ergodic phases of the 1D chain. Hence, we propose the use of a central spin as a possible experimental probe to identify the MBL phase.

[52]
Title: Continuous degeneracy of the fcc kagome lattice with magnetic dipolar interactions
Subjects: Materials Science (cond-mat.mtrl-sci)

Results are presented on analytic and computational analyses of the spin states associated with a 3D fcc lattice composed of ABC stacked kagome planes of magnetic ions with only long-range dipole-dipole interactions. Extending previous work on the 2D kagome system, where discrete six-fold discrete degeneracy of the ground state was revealed [Holden et al. Phys. Rev. B 91, 224425 (2015)], we show that the 3D lattice exhibits a continuous degeneracy characterized by just two spherical angles involving six sublattice spin vectors. Application of a Heat Bath Monte Carlo algorithm shows that thermal fluctuations reduce this degeneracy at very low temperature in an order-by-disorder process. A magnetic field applied along directions of high symmetry also results in lifting the continuous degeneracy to a subset of states from the original set of ground states. Metropolis Monte Carlo simulation results are also presented on the temperature and system size dependence of the energy, specific heat, and magnetization, providing evidence for a phase transition at T $\simeq$ 0.38 (in units of the dipole strength). The results can be relevant to a class of magnetic compounds having the AuCu$_3$ crystal structure.

[53]
Title: Unconventional Spin-Wave Phenomena Induced by a Periodic Dzyaloshinskii-Moriya Interaction
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Other Condensed Matter (cond-mat.other); Soft Condensed Matter (cond-mat.soft)

Periodically patterned metamaterials are known for exhibiting wave properties similar to the ones observed in electronic band structures in crystal lattices. In particular, periodic ferromagnetic mate- rials are characterized by the presence of bands and bandgaps in their spin-wave spectrum at tunable GHz frequencies. Recently, the fabrication of magnets hosting Dzyaloshinskii-Moriya interactions has been pursued with high interest since properties such as the stabilization of chiral spin tex- tures and nonreciprocal spin-wave propagation emerge from this antisymmetric exchange coupling. In this context, to further engineer the magnon band structure, we propose the implementation of magnonic crystals with periodic Dzyaloshinskii-Moriya interactions, which can be obtained, for instance, via patterning of periodic arrays of heavy-metals wires on top of an ultrathin magnetic film. We demonstrate through theoretical calculations and micromagnetic simulations that such systems show an unusual evolution of the standing spin waves around the gaps in areas of the film that are in contact with the heavy-metal wires. We also predict the emergence of indirect gaps and flat bands and, effects that depend on the strength of the Dzyaloshinskii-Moriya interaction. This study opens new routes towards engineered metamaterials for spin-wave-based devices.

[54]
Title: Spin-flop phase transition in the orthorhombic antiferromagnetic topological semimetal Cu0.95MnAs
Subjects: Strongly Correlated Electrons (cond-mat.str-el)

The orthorhombic antiferromagnetic compound CuMnAs was recently predicted to be an antiferromagnetic Dirac semimetal if both the Ry gliding and S2z rotational symmetries are preserved in its magnetic ordered state. In our previous work on Cu0.95MnAs and Cu0.98Mn0.96As, we showed that in their low temperature commensurate antiferromagnetic state the b axis is the magnetic easy axis, which breaks the S2z symmetry. As a result, while the existence of Dirac fermions is no longer protected, the polarized surface state makes this material potentially interesting for antiferromagnetic spintronics. In this paper, we report a detailed study of the anisotropic magnetic properties and magnetoresistance of Cu0.95MnAs and Cu0.98Mn0.96As. Our study shows that in Cu0.95MnAs the b axis is the easy axis and the c axis is the hard axis. Furthermore, it reveals that Cu0.95MnAs features a spin-flop phase transition at high temperatures and low fields when the field is applied along the easy b axis, resulting in canted antiferromagnetism. However, no metamagnetic transition is observed in Cu0.98Mn0.96As, indicating that the magnetic interactions in this system are very sensitive to Cu vacancies and Cu/Mn site mixing.

[55]
Title: Strange metallicity in the doped Hubbard model
Subjects: Strongly Correlated Electrons (cond-mat.str-el)

Strange or bad metallic transport, defined by its incompatibility with conventional quasiparticle pictures, is a theme common to strongly correlated materials and ubiquitous in many high temperature superconductors. The Hubbard model represents a minimal starting point for modeling strongly correlated systems. Here we demonstrate strange metallic transport in the doped two-dimensional Hubbard model using determinantal quantum Monte Carlo calculations. Over a wide range of doping, we observe resistivities exceeding the Mott-Ioffe-Regel limit with linear temperature dependence. The temperatures of our calculations extend to as low as 1/40 the non-interacting bandwidth, placing our findings in the degenerate regime relevant to experimental observations of strange metallicity. Our results provide a foundation for connecting theories of strange metals to models of strongly correlated materials.

Cross-lists for Fri, 22 Jun 18

[56]  arXiv:1806.07748 (cross-list from math-ph) [pdf, other]
Title: Equivalent T-Q relations and exact results for the open TASEP
Subjects: Mathematical Physics (math-ph); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Theory (hep-th)

Starting from the Bethe ansatz solution for the open Totally Asymmetric Simple Exclusion Process (TASEP), we compute the largest eigenvalue of the deformed Markovian matrix, in exact agreement with results obtained by the matrix ansatz. We also compute the eigenvalues of the higher conserved charges. The key step is to find a simpler equivalent T-Q relation, which is similar to the one for the TASEP with periodic boundary conditions.

[57]  arXiv:1806.07879 (cross-list from q-bio.NC) [pdf, ps, other]
Title: Integrated information in the thermodynamic limit
Subjects: Neurons and Cognition (q-bio.NC); Disordered Systems and Neural Networks (cond-mat.dis-nn); Statistical Mechanics (cond-mat.stat-mech); Adaptation and Self-Organizing Systems (nlin.AO); Biological Physics (physics.bio-ph)

The ability to integrate information into a unified coherent whole is a fundamental capacity of many biological and cognitive systems. Integrated Information Theory (IIT) provides a mathematical approach to quantify the level of integration in a system. Nevertheless, it is not yet well understood how integration scales up with the size of a system or with different temporal scales of activity, nor how a system maintains its integration as its interacts with its environment. We argue that modelling and understanding how measures of information integration operate in these scenarios is fundamental to adequately capture integration in systems such as the brain. We propose a simplified and modified version of integrated information {\phi} in order to explore these questions. Using mean field approximations, we measure {\phi} in a kinetic Ising models of infinite size. We find that information integration diverges in some cases when the system is near critical points in continuous phase transitions. Moreover, we find that we can delimit the boundary of a system with respect to its environment by comparing the divergent integrative tendencies of system and system-environment processes respectively. Finally, we model a system that maintains integrated information when interacting with a range of different environments by generating a critical surface spanning a parametric region of the environment. We conclude by discussing how thinking about integrated information in the thermodynamic limit opens fruitful research avenues for studying the organization of biological and cognitive systems.

[58]  arXiv:1806.07903 (cross-list from q-bio.NC) [pdf, other]
Title: Finding influential nodes for integration in brain networks using optimal percolation theory
Comments: 20 pages, 6 figures, Supplementary Info
Journal-ref: Nature Communications, 9, 2274, (2018)
Subjects: Neurons and Cognition (q-bio.NC); Disordered Systems and Neural Networks (cond-mat.dis-nn); Biological Physics (physics.bio-ph)

Global integration of information in the brain results from complex interactions of segregated brain networks. Identifying the most influential neuronal populations that efficiently bind these networks is a fundamental problem of systems neuroscience. Here we apply optimal percolation theory and pharmacogenetic interventions in-vivo to predict and subsequently target nodes that are essential for global integration of a memory network in rodents. The theory predicts that integration in the memory network is mediated by a set of low-degree nodes located in the nucleus accumbens. This result is confirmed with pharmacogenetic inactivation of the nucleus accumbens, which eliminates the formation of the memory network, while inactivations of other brain areas leave the network intact. Thus, optimal percolation theory predicts essential nodes in brain networks. This could be used to identify targets of interventions to modulate brain function.

[59]  arXiv:1806.07920 (cross-list from physics.app-ph) [pdf, other]
Title: Tunable Rydberg excitons maser
Subjects: Applied Physics (physics.app-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)

We propose a solid state maser based on Cu2O, where ensemble of highly excited Rydberg exciton states serves as a gain medium. We show that the system is highly tunable with external electric field, allowing for a wide range of emission frequencies. Numerical simulations of system dynamics are performed to optimize the conditions for efficient masing and estimate the emission power.

[60]  arXiv:1806.07930 (cross-list from quant-ph) [pdf, other]
Title: Digital coherent control of a superconducting qubit
Comments: 13 pages, 9 figures, 1 table
Subjects: Quantum Physics (quant-ph); Superconductivity (cond-mat.supr-con)

High-fidelity gate operations are essential to the realization of a fault-tolerant quantum computer. In addition, the physical resources required to implement gates must scale efficiently with system size. A longstanding goal of the superconducting qubit community is the tight integration of a superconducting quantum circuit with a proximal classical cryogenic control system. Here we implement coherent control of a superconducting transmon qubit using a Single Flux Quantum (SFQ) pulse driver cofabricated on the qubit chip. The pulse driver delivers trains of quantized flux pulses to the qubit through a weak capacitive coupling; coherent rotations of the qubit state are realized when the pulse-to-pulse timing is matched to a multiple of the qubit oscillation period. We measure the fidelity of SFQ-based gates to be ~95% using interleaved randomized benchmarking. Gate fidelities are limited by quasiparticle generation in the dissipative SFQ driver. We characterize the dissipative and dispersive contributions of the quasiparticle admittance and discuss mitigation strategies to suppress quasiparticle poisoning. These results open the door to integration of large-scale superconducting qubit arrays with SFQ control elements for low-latency feedback and stabilization.

[61]  arXiv:1806.08066 (cross-list from physics.bio-ph) [pdf, other]
Title: Dimensionality-dependent crossover in motility of polyvalent burnt-bridges ratchets
Comments: Includes SI, but not supporting movies
Subjects: Biological Physics (physics.bio-ph); Statistical Mechanics (cond-mat.stat-mech); Subcellular Processes (q-bio.SC)

The burnt-bridges ratchet (BBR) mechanism is a model for biased molecular motion whereby the construct destroys track binding sites as it progresses, and therefore acts as a diffusing forager, seeking new substrate sites. Using Monte Carlo simulations that implement the Gillespie algorithm, we investigate the kinetic characteristics of simple polyvalent BBRs as they move on tracks of increasing width. We find that as the track width is increased the BBRs remain nearly ballistic for considerable track widths proportional to the span (leg length) of the polyvalent walker, before transitioning to near-conventional diffusion on two-dimensional tracks. We find there exists a tradeoff in BBR track association time and superdiffusivity in the BBR design parameter space of span, polyvalency and track width. Furthermore, we develop an analytical model to describe the ensembleaverage motion on the track and find it is in good agreement with our Gillespie simulation results. This work offers insights into design criteria for de novo BBRs and their associated tracks, where experimentalists seek to optimize directionality and track association time.

[62]  arXiv:1806.08068 (cross-list from physics.comp-ph) [pdf, ps, other]
Title: A simple and efficient numerical procedure to compute the inverse Langevin function with high accuracy
Subjects: Computational Physics (physics.comp-ph); Soft Condensed Matter (cond-mat.soft)

The inverse Langevin function is a fundamental part of the statistical chain models used to describe the behavior of polymeric-like materials, appearing also in other fields such as magnetism, molecular dynamics and even biomechanics. In the last four years, several approximants of the inverse Lanvegin function have been proposed. In most of them, optimization techniques are used to reduce the relative error of previously published approximants to reach orders of magnitude of order 1E-3% to 1E-2% In this paper a new simple and efficient numerical approach to calculate the inverse Langevin function is proposed. Its main feature is the drastic reduction of the maximum relative error in all the domain [0,1), halving also the function evaluation times. Specifically, in [0,0.96], the order of magnitude of the maximum relative error is order 1E-9%, which corresponds with a maximum absolute error of order 1E-14, whereas within [0.91,1) the relative error is of order 1E-7%. The method consists in the discretization of the Langevin function, the calculation of the inverse of these discretization points and their interpolation by cubic splines. In order to reproduce the asymptotic behavior of the inverse Langevin function, a [2/1] rational function is considered only in the asymptotic zone and with the same C2 continuity requirements as cubic splines. The use of these C2 piecewise cubic polynomials ensures the continuity of the function up to the second derivative and its integration in any interval.

[63]  arXiv:1806.08162 (cross-list from physics.app-ph) [pdf, other]
Title: The electrical conductivity tensor of $β$-Ga$_{2}$O$_{3}$ analyzed by van der Pauw measurements: Inherent anisotropy, off-diagonal element, and the impact of grain boundaries
Subjects: Applied Physics (physics.app-ph); Materials Science (cond-mat.mtrl-sci)

The semiconducting oxide $\beta$-Gallium Oxide ($\beta$-Ga$_{2}$O$_{3}$) possesses a monoclinic unit cell whose low symmetry generally leads to anisotropic physical properties. For example, its electrical conductivity is generally described by a polar symmetrical tensor of second rank consisting of four independent components. Using van der Pauw measurements in a well-defined square geometry on differently-oriented high-quality bulk samples and the comparison to finite element simulations we determine the ratio of all elements of the $\beta$-Ga$_{2}$O$_{3}$ 3-dimensional electrical conductivity tensor. Despite the structural anisotropy a nearly isotropic conductivity was found with the principal conductivities deviating from each other by less than 5 % and the off-diagonal element being less than 4 % of the diagonal ones. Analysis of the temperature dependence of the anisotropy and mobility of differently doped samples suggest this isotropic behavior to apply for phonon-scattering as well as ionized-impurity scattering. We demonstrate that significantly higher anisotropies can be caused by extended structural defects in the form of low-angle grain boundaries for which we determined energy barriers of multiple 10 meV.

[64]  arXiv:1806.08280 (cross-list from physics.optics) [pdf]
Title: Fourier plane optical microscopy and spectroscopy
Comments: Submitted to Wiley VCH encyclopedia of applied physics
Subjects: Optics (physics.optics); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Applied Physics (physics.app-ph)

Intensity, wavevector, phase, and polarization are the most important parameters of any light beam. Understanding the wavevector distribution has emerged as a very important problem in recent days, especially at nanoscale. It provides unique information about the light-matter interaction. Back focal plane or Fourier plane imaging and spectroscopy techniques help to measure wavevector distribution not only from single molecules and single nanostructures but also from metasurfaces and metamaterials. This review provides a birds-eye view on the technique of back focal imaging and spectroscopy, different methodologies used in developing the technique and applications including angular emission patterns of fluorescence and Raman signals from molecules, elastic scattering etc. We first discuss on the information one can obtain at the back focal plane of the objective lens according to both imaging and spectroscopy viewpoints and then discuss the possible configurations utilized to project back focal plane of the objective lens onto the imaging camera or to the spectroscope. We also discuss the possible sources of error in such measurements and possible ways to overcome it and then elucidate the possible applications.

Replacements for Fri, 22 Jun 18

[65]  arXiv:1607.02242 (replaced) [pdf, other]
Title: Global topology of Weyl semimetals and Fermi arcs
Comments: 9 pages, 4 figures, JPhysA Highlight in 2017, Free access in 2018
Journal-ref: J.Phys.A: Math.Theor.(Letter) vol.50 (2017) 11LT01 (11pp)
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics - Theory (hep-th); Mathematical Physics (math-ph)
[66]  arXiv:1611.05127 (replaced) [pdf]
Title: Quantized Ballistic Transport of Electrons and Electron Pairs in LaAlO$_3$/SrTiO$_3$ Nanowires
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall); Materials Science (cond-mat.mtrl-sci); Strongly Correlated Electrons (cond-mat.str-el); Superconductivity (cond-mat.supr-con); Quantum Physics (quant-ph)
[67]  arXiv:1612.07981 (replaced) [pdf, other]
Title: Density functional theory study of vacancy induced magnetism in Li$_{3}$N
Journal-ref: Romanian Journal of Physics 62, 607 (2017)
Subjects: Materials Science (cond-mat.mtrl-sci)
[68]  arXiv:1703.00040 (replaced) [pdf, other]
Title: Revisiting universality of the liquid-gas critical point in 2D
Comments: replaced with published version. Typos corrected
Journal-ref: Phys. Rev. E 96, 062124 (2017)
Subjects: Statistical Mechanics (cond-mat.stat-mech)
[69]  arXiv:1707.04120 (replaced) [pdf, ps, other]
Title: Simulating polaron biophysics with Rydberg atoms
Journal-ref: Sci. Rep. 8, 9247 (2018)
Subjects: Atomic Physics (physics.atom-ph); Quantum Gases (cond-mat.quant-gas); Pattern Formation and Solitons (nlin.PS)
[70]  arXiv:1707.09722 (replaced) [pdf, other]
Title: Quantum coarse-grained entropy and thermodynamics
Subjects: Quantum Physics (quant-ph); Quantum Gases (cond-mat.quant-gas); Statistical Mechanics (cond-mat.stat-mech)
[71]  arXiv:1708.02475 (replaced) [pdf, ps, other]
Title: Surface charge conductivity of topological insulator in a magnetic field: effect of hexagonal warping
Journal-ref: Phys. Rev. B 97, 075421 (2018)
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
[72]  arXiv:1708.03235 (replaced) [pdf, ps, other]
Title: Magnetic anisotropy of the alkali iridate Na$_{2}$IrO$_{3}$ at high magnetic fields: evidence for strong ferromagnetic Kitaev correlations
Comments: 12 pages, 20 figures; three figures in the main text modified, two new sections and two tables added to the appendix
Subjects: Strongly Correlated Electrons (cond-mat.str-el)
[73]  arXiv:1709.08376 (replaced) [pdf, other]
Title: Asymmetric $g$ tensor in low-symmetry two-dimensional hole systems
Journal-ref: Phys. Rev. X 8, 021068 (2018)
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
[74]  arXiv:1710.03007 (replaced) [pdf, other]
Title: Huge magnetoresistance and ultra-sharp metamagnetic transition in polycrystalline ${Sm_{0.5}Ca_{0.25}Sr_{0.25}MnO_3}$
Comments: NPG Asia Materials (accepted on 13th June 2018)
Subjects: Materials Science (cond-mat.mtrl-sci)
[75]  arXiv:1710.07595 (replaced) [pdf, other]
Title: Robust non-Abelian spin liquid and possible intermediate phase in antiferromagnetic Kitaev model with magnetic field
Journal-ref: Phys. Rev. B 97, 241110(R) (2018)
Subjects: Strongly Correlated Electrons (cond-mat.str-el)
[76]  arXiv:1710.09265 (replaced) [pdf]
Title: Emergence of the interplay between hierarchy and contact splitting in biological adhesion highlighted through a hierarchical shear lag model
Comments: 33 pages, 7 figures, 1 table in press
Journal-ref: Soft Matter, (2018)
Subjects: Soft Condensed Matter (cond-mat.soft)
[77]  arXiv:1711.06904 (replaced) [pdf]
Title: A Study Concerning the Electronic Conductivity in Eumelanin Thin Films
Subjects: Applied Physics (physics.app-ph); Soft Condensed Matter (cond-mat.soft)
[78]  arXiv:1711.09132 (replaced) [pdf, other]
Title: Multiparameter Gaussian Quantum Metrology
Comments: 14 pages, 3 figures; expanded and updated; to appear in Physical Review A
Subjects: Quantum Physics (quant-ph); Statistical Mechanics (cond-mat.stat-mech); Mathematical Physics (math-ph); Instrumentation and Detectors (physics.ins-det); Optics (physics.optics)
[79]  arXiv:1712.07715 (replaced) [pdf, other]
Title: Entanglement in 3D Kitaev Spin Liquids
Comments: 11 pages, 13 figures, v2: additional figure, minor revisions, published version
Journal-ref: J. Stat. Mech. (2018) 063101
Subjects: Strongly Correlated Electrons (cond-mat.str-el)
[80]  arXiv:1801.01099 (replaced) [pdf, other]
Title: Spin and mass superfluidity in ferromagnetic spin-1 Bose-Einstein condensate
Authors: E. B. Sonin
Comments: 13 pages, 6 figures, revised version published in Phys. Rev. B
Journal-ref: Phys. Rev. B, 97, 224517 (2018)
Subjects: Quantum Gases (cond-mat.quant-gas)
[81]  arXiv:1801.10397 (replaced) [pdf, ps, other]
Title: Spin susceptibility of three-dimensional Dirac semimetals
Journal-ref: Phys. Rev. B 97, 245207 (2018)
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
[82]  arXiv:1802.08440 (replaced) [pdf]
Title: Tuning the electronic and chemisorption properties of hexagonal MgO nanotubes by doping - Theoretical study
Authors: Aleksandar Jovanović (1 and 2), Milena Petković (1), Igor A. Pašti (1 and 3), Börje Johansson (3 and 4 and 5), Natalia V.Skorodumova (3 and 4) ((1) University of Belgrade - Faculty of Physical Chemistry, Belgrade, Serbia, (2) CEST Kompetenzzentrum für elektrochemische Oberflächentechnologie GmbH, Wiener Neustadt, Austria, (3) Department of Materials Science and Engineering, School of Industrial Engineering and Management, KTH - Royal Institute of Technology, Stockholm, Sweden, (4) Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden, (5) Humboldt University, Physics Department, Berlin, Germany)
Comments: 23 pages, 8 figures, 3 tables, 45 references, included Supplementary Information (8 pages, 2 figures, 12 tables); submitted to Applied Surface Science
Subjects: Materials Science (cond-mat.mtrl-sci)
[83]  arXiv:1803.02561 (replaced) [pdf, other]
Title: Theory of the optical spinpolarization loop of the nitrogen-vacancy center in diamond
Comments: 13 pages, 6 figures, 1 table
Subjects: Quantum Physics (quant-ph); Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
[84]  arXiv:1803.03942 (replaced) [pdf, other]
Title: Self-organized system-size oscillation of a stochastic lattice-gas model
Subjects: Biological Physics (physics.bio-ph); Statistical Mechanics (cond-mat.stat-mech); Subcellular Processes (q-bio.SC)
[85]  arXiv:1803.09732 (replaced) [pdf, ps, other]
Title: Ground-state properties of dilute Bose systems with synthetic dispersion laws
Comments: 6 pages, version to be published in Phys. Rev. A
Subjects: Quantum Gases (cond-mat.quant-gas)
[86]  arXiv:1804.00674 (replaced) [pdf, other]
Title: Importance of orbital fluctuations for the magnetic dynamics in heavy-fermion compound SmB$_6$
Journal-ref: Phys. Rev. B 97, 241107 (2018)
Subjects: Strongly Correlated Electrons (cond-mat.str-el)
[87]  arXiv:1804.04506 (replaced) [pdf, other]
Title: Few-fermion thermometry
Journal-ref: Phys. Rev. A 97, 063619 (2018)
Subjects: Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)
[88]  arXiv:1804.10358 (replaced) [pdf, other]
Title: Measuring Hopf links and Hopf invariants in a quenched topological Raman lattice
Authors: Jinlong Yu
Subjects: Quantum Gases (cond-mat.quant-gas)
[89]  arXiv:1805.05109 (replaced) [pdf, other]
Title: Multi-loop techniques for massless Feynman diagram calculations
Comments: Review article. LaTeX file with feynMF package. (v2) references added and minor typos corrected. 65 pages, 8 figures. (v1) 64 pages, 8 figures
Subjects: High Energy Physics - Theory (hep-th); Statistical Mechanics (cond-mat.stat-mech); High Energy Physics - Phenomenology (hep-ph)
[90]  arXiv:1805.07271 (replaced) [pdf, other]
Title: The role of electron-vibron interaction and local pairing in conductivity and superconductivity of alkali-doped fullerides
Comments: 22 pages, 9 figures. arXiv admin note: text overlap with arXiv:1610.08233
Subjects: Superconductivity (cond-mat.supr-con)
[91]  arXiv:1805.11226 (replaced) [pdf, ps, other]
Title: Non-thermodynamic nature of the orbital angular momentum in neutral fermionic superfluids
Comments: 15 pages, 8 figures, to be published in Phys. Rev. B
Subjects: Superconductivity (cond-mat.supr-con); Strongly Correlated Electrons (cond-mat.str-el)
[92]  arXiv:1806.00876 (replaced) [pdf, ps, other]
Title: A modular-invariant modified Weierstrass sigma-function as a building block for lowest-Landau-level wavefunctions on the torus
Authors: F. D. M. Haldane
Comments: 5 pages, no figures. Revised to reference and describe a connection to Eisenstein's "periodic completion"of the Weierstrass zeta function
Subjects: Mathematical Physics (math-ph); Strongly Correlated Electrons (cond-mat.str-el)
[93]  arXiv:1806.04023 (replaced) [pdf, other]
Title: Higher-order topological insulators protected by (roto)inversion symmetries
Subjects: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
[94]  arXiv:1806.05150 (replaced) [pdf, other]
Title: Phase-locking between different partial-waves in atom-ion spin-exchange collisions
Comments: 5 pages, 5 figures and Supplemental Material
Subjects: Atomic Physics (physics.atom-ph); Quantum Gases (cond-mat.quant-gas); Quantum Physics (quant-ph)
[95]  arXiv:1806.05587 (replaced) [pdf, other]
Title: Quantum theory of mechanical deformations