We investigate the behavior of sulfur vacancy defects, the most abundant type of intrinsic defect in monolayer ${\mathrm{MoS}}_{2}$, using first-principles calculations based on density functional theory. We consider the dependence of the isolated defect formation energy on the charge state and on uniaxial tensile …

[Phys. Rev. B 95, 014106] Published Tue Jan 17, 2017

]]>Spin nematic phase is a phase of frustrated quantum magnets with a quadrupolar order of electron spins. Since the spin nematic order is usually masked in experimentally accessible quantities, it is important to develop a methodology for detecting the spin nematic order experimentally. In this paper …

[Phys. Rev. B 95, 014416] Published Tue Jan 17, 2017

]]>$\mathrm{G}{\mathrm{e}}_{1-x}\mathrm{M}{\mathrm{n}}_{x}$ (GeMn) granular thin films are a unique and promising material for spintronic applications owing to their large positive magnetoresistance (MR). Previous studies of GeMn have suggested that the large MR is related to the nanospinodal decomposition of GeMn into Mn-rich ferromagnetic nanopart…

[Phys. Rev. B 95, 014417] Published Tue Jan 17, 2017

]]>We introduce a type of topological magnon matter: the magnonic pendant to electronic nodal-line semimetals. Magnon spectra of anisotropic pyrochlore ferromagnets feature twofold degeneracies of magnon bands along a closed loop in reciprocal space. These magnon nodal lines are topologically protected…

[Phys. Rev. B 95, 014418] Published Tue Jan 17, 2017

]]>The recently discovered high-${T}_{c}$ superconductor ${\mathrm{Ca}}_{1-x}{\mathrm{La}}_{x}{\mathrm{FeAs}}_{2}$ is a unique compound not only because of its low-symmetry crystal structure but also because of its electronic structure, which hosts Dirac-like metallic bands resulting from (spacer) zigzag As chains. We present a comprehensive first-prin…

[Phys. Rev. B 95, 014511] Published Tue Jan 17, 2017

]]>We report first-principles calculations of the superconducting properties of $\beta -{\mathrm{Bi}}_{2}\mathrm{Pd}$ within the fully anisotropic Migdal-Eliashberg formalism. We find a single anisotropic superconducting gap of $s$-wave symmetry which varies in magnitude on the different regions of the Fermi surface. The calculated s…

[Phys. Rev. B 95, 014512] Published Tue Jan 17, 2017

]]>Using a nonperturbative functional renormalization-group approach to the two-dimensional quantum $\mathrm{O}(N$) model, we compute the low-frequency limit $\omega \to 0$ of the zero-temperature conductivity in the vicinity of the quantum critical point. Our results are obtained from a derivative expansion to second order…

[Phys. Rev. B 95, 014513] Published Tue Jan 17, 2017

]]>We observed and studied pinned uncompensated magnetization in an antiferromagnet using magnetoresistance measurements. For this, we developed antiferromagnet-ferromagnet spin valves (AFSVs) that consist of an antiferromagnetic layer and a ferromagnetic one, separated by a nonmagnetic conducting spac…

[Phys. Rev. B 95, 020409(R)] Published Tue Jan 17, 2017

]]>Multiple bosons undergoing coherent evolution in a coupled network of sites constitute a so-called quantum walk system. The simplest example of such a two-particle interference is the celebrated Hong-Ou-Mandel interference. When scaling to larger boson numbers, simulating the exact distribution of b…

[Phys. Rev. B 95, 020502(R)] Published Tue Jan 17, 2017

]]>This work addresses the one-dimensional problem of Bloch electrons when they are rapidly driven by a homogeneous time-periodic light and linearly coupled to vibrational modes. Starting from a generic time-periodic electron-phonon Hamiltonian, we derive a time-independent effective Hamiltonian that d…

[Phys. Rev. B 95, 024306] Published Tue Jan 17, 2017

]]>We have successfully synthesized single crystals of ${\mathrm{EuNi}}_{5}{\mathrm{As}}_{3}$ using a flux method, and we present a comprehensive study of the physical properties using magnetic susceptibility, specific heat, electrical resistivity, thermoelectric power, and x-ray absorption spectroscopy (XAS) measurements. ${\mathrm{EuNi}}_{5}{\mathrm{As}}_{3}$…

[Phys. Rev. B 95, 024416] Published Tue Jan 17, 2017

]]>The concept of temperature in nonequilibrium thermodynamics is an outstanding theoretical issue. We propose an energy repartition principle that leads to a spectral (mode-dependent) temperature in steady-state nonequilibrium systems. The general concepts are illustrated by analytic solutions of the …

[Phys. Rev. B 95, 024417] Published Tue Jan 17, 2017

]]>We discuss the nodal structure of odd-parity superconductors in the presence of nonsymmorphic crystal symmetries, both with and without spin-orbit coupling, and with and without time-reversal symmetry. We comment on the relation of our work to previous work in the literature, and also the implicatio…

[Phys. Rev. B 95, 024508] Published Tue Jan 17, 2017

]]>The classic composite fermion field theory [B. I. Halperin, P. A. Lee, and N. Read, Phys. Rev. B **47**, 7312 (1993)] builds up an excellent framework to uniformly study important physical objects and globally explain anomalous experimental phenomena in fractional quantum Hall physics while there are al…

[Phys. Rev. B 95, 035123] Published Tue Jan 17, 2017

]]>We report on numerically exact determinantal quantum Monte Carlo simulations of the onset of spin-density-wave (SDW) order in itinerant electron systems captured by a sign-problem-free two-dimensional lattice model. Extensive measurements of the SDW correlations in the vicinity of the phase transiti…

[Phys. Rev. B 95, 035124] Published Tue Jan 17, 2017

]]>We present a general picture of the exciton properties of layered materials in terms of the excitations of their single-layer building blocks. To this end, we derive a model excitonic Hamiltonian by drawing an analogy with molecular crystals, which are other prototypical van der Waals materials. We …

[Phys. Rev. B 95, 035125] Published Tue Jan 17, 2017

]]>We report a diagrammatic method to solve the general problem of calculating configurationally averaged Green's function correlators that appear in quantum transport theory for nanostructures containing disorder. The theory treats both equilibrium and nonequilibrium quantum statistics on an equal foo…

[Phys. Rev. B 95, 035126] Published Tue Jan 17, 2017

]]>The conducting gas that forms at the interface between ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ has proven to be a fertile playground for a wide variety of physical phenomena. The bulk of previous research has focused on the (001) and (110) crystal orientations. Here we report detailed measurements of the low-temperature …

[Phys. Rev. B 95, 035127] Published Tue Jan 17, 2017

]]>Uniaxial compressive strain along the [001] direction strongly suppresses the spin relaxation in silicon. When the strain level is large enough so that electrons are redistributed only in the two valleys along the strain axis, the dominant scattering mechanisms are quenched and electrons mainly expe…

[Phys. Rev. B 95, 035204] Published Tue Jan 17, 2017

]]>Quantum dots are promising building blocks for future optoelectronics or quantum information applications. Many of their properties derive from the quantum state of the hole trapped in the dot. “Light” and “heavy” hole states differ by the anisotropic character of their spin and of the electric dipole they form with a trapped electron. Light holes are of particular interest as they offer extended opportunities for optical manipulation of single carriers, or the electrical manipulation of magnetic objects. Here, the authors demonstrate that the hole ground state can be engineered through a proper design of the strain built in the dot when inserted inside a nanowire of a different lattice parameter. Two complementary techniques provide evidence of a light hole state: polarization-resolved Fourier imaging, which is sensitive to the nature of the electron-hole electric dipole, and magneto-optical spectroscopy, which probes the hole spin state through its coupling to magnetic atoms.

[Phys. Rev. B 95, 035305] Published Tue Jan 17, 2017

]]>We develop a microscopic large-$N$ theory of electron-electron interaction corrections to multilegged Feynman diagrams describing second- and third-order non-linear-response functions. Our theory, which reduces to the well-known random-phase approximation in the linear-response limit, is completely ge…

[Phys. Rev. B 95, 035416] Published Tue Jan 17, 2017

]]>Monolayer two-dimensional transition metal dichalcogenide (TMDCs) exhibit exceptionally strong spin-orbit and electron-electron interaction effects and have provided a rich new playground for the exploration of exciton physics. Recent experiments have demonstrated that in the presence of excess charge carriers the prominent excitonic features in optical absorption split into two separate peaks. The appearance of the additional peak is usually attributed to the presence of trions, charged fermionic quasiparticles formed by binding two electrons to one hole or two holes to one electron. The authors here argue that in the density range for which amplitudes of two peaks are comparable three-particle physics is of importance, and the appropriate picture is one of excitons interacting with the Fermi sea formed by additional charge carriers. These interactions result in the dressing of excitons into exciton-polarons. The exciton spectrum splits into a lower energy attractive exciton-polaron branch, normally identified as a trion branch, and a higher energy repulsive exciton-polaron branch, normally identified as an exciton branch. The authors provide a complete theory of absorption, which incorporates both static and dynamic effects of Fermi sea, and analyze frequency and doping dependence of optical conductivity in detail. The calculated density dependence of peak splitting and their amplitudes and widths are in agreement with recent experiments.

[Phys. Rev. B 95, 035417] Published Tue Jan 17, 2017

]]>[Phys. Rev. B 95, 039903] Published Tue Jan 17, 2017

]]>The core issue for the implementation of NV center qubit technology is a sensitive readout of the NV spin state. We present here a detailed theoretical and experimental study of NV center photoionization processes, used as a basis for the design of a dual-beam photoelectric method for the detection …

[Phys. Rev. B 95, 041402(R)] Published Tue Jan 17, 2017

]]>We construct a many-body theory of magnetoelasticity in one dimension and show that the dynamical correlation functions of the quantum magnet, connecting the spins with phonons, involve all energy scales. Accounting for all magnetic states nonperturbatively via the exact diagonalization techniques o…

[Phys. Rev. B 95, 045120] Published Tue Jan 17, 2017

]]>We investigate the phase transition between an ergodic and a many-body localized phase in infinite anisotropic spin-$1/2$ Heisenberg chains with binary disorder. Starting from the Néel state, we analyze the decay of antiferromagnetic order ${m}_{s}\left(t\right)$ and the growth of entanglement entropy ${S}_{\mathrm{ent}}\left(t\right)$ during un…

[Phys. Rev. B 95, 045121] Published Tue Jan 17, 2017

]]>We examine normal-state quasiparticle excitations along the $\mathrm{\Gamma}\text{\u2212}M$ cut in momentum space for the putative $p$-wave superconductor ${\mathrm{Sr}}_{2}{\mathrm{RuO}}_{4}$ on the basis of fluctuation exchange approximation calculations. We take as input first-principles derived parameters for the band structure and spin-orbit and electro…

[Phys. Rev. B 95, 045122] Published Tue Jan 17, 2017

]]>Achieving true bulk insulating behavior in ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$, the archetypal topological insulator with a simplistic one-band electronic structure and sizable band gap, has been prohibited by a well-known self-doping effect caused by selenium vacancies, whose extra electrons shift the chemical potential into t…

[Phys. Rev. B 95, 045123] Published Tue Jan 17, 2017

]]>We investigate Dirac-like conical dispersions in photonic crystals with complex unit cells. Comparing with photonic crystals with simple unit cells, the complex-unit-cell design can provide extra degrees of freedom to engineer the frequency of the Dirac-like point in a broad frequency regime. Intere…

[Phys. Rev. B 95, 045124] Published Tue Jan 17, 2017

]]>We investigate the out-of-equilibrium dynamics after a local quench that connects two spin-1/2 XXZ chains prepared in the ground state of the Hamiltonian in different phases, one in the ferromagnetic phase and the other in the critical phase. We analyze the time evolution of the on-site magnetizatio…

[Phys. Rev. B 95, 045125] Published Tue Jan 17, 2017

]]>We investigate ZnO, CdO, and MgO oxides crystallizing in rocksalt, wurtzite, and zincblende structures. Whereas in MgO calculations, the conventional LDA-1/2 method is employed through a self-energy potential $\left({V}_{S}\right)$, the shallow $d$ bands in ZnO and CdO are treated through an increased amplitude $\left(A\right)$ of ${\dots}_{}$

[Phys. Rev. B 95, 045126] Published Tue Jan 17, 2017

]]>One of the remarkable interaction effects on topological insulators is the reduction of topological classification in free-fermion systems. We address this issue in a bilayer honeycomb lattice model by taking into account temperature effects on the reduction. Our analysis, based on the real-space dy…

[Phys. Rev. B 95, 045127] Published Tue Jan 17, 2017

]]>We report a study of the magnetic and magnetotransport properties of layered transition-metal pnictide ${\mathrm{CaMnSb}}_{2}$. ${\mathrm{CaMnSb}}_{2}$ is a quasi-two-dimensional system with an orthorhombic crystal structure, containing two distinct layers of a distorted Sb square sheet and an edge-sharing ${\mathrm{MnSb}}_{4}$ tetrahedron. It wa…

[Phys. Rev. B 95, 045128] Published Tue Jan 17, 2017

]]>We report ${T}_{2}$ spin coherence times for electronic states localized in Si vacancies in $4H\text{\u2212}\mathrm{SiC}$. Our spin coherence study included two SiC samples that were irradiated with 2 MeV protons at different fluences (${10}^{13}$ and ${10}^{14}\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{-2}$) in order to create samples with unique defect concentrations. Using optical…

[Phys. Rev. B 95, 045206] Published Tue Jan 17, 2017

]]>We address the intrinsic optical properties of hexagonal boron nitride in deep ultraviolet. We show that the fine structure of the phonon replicas arises from overtones involving up to six low-energy interlayer shear modes. These lattice vibrations are specific to layered compounds since they corres…

[Phys. Rev. B 95, 045207] Published Tue Jan 17, 2017

]]>We investigate flux qubits driven by a biharmonic magnetic signal, with a phase lag that acts as an effective time reversal broken parameter. The driving induced transition rate between the ground and the excited state of the flux qubit can be thought of as an effective transmittance, profiting from…

[Phys. Rev. B 95, 045412] Published Tue Jan 17, 2017

]]>We study the effect of Rashba spin-orbit coupling (SOC) on the charge and spin degrees of freedom of a quasi-one-dimensional (quasi-1D) Wigner crystal. As electrons in a quasi-1D Wigner crystal can move in the transverse direction, SOC cannot be gauged away in contrast to the pure 1D case. We show t…

[Phys. Rev. B 95, 045413] Published Tue Jan 17, 2017

]]>It is known that there are lattice models in which noninteracting particles get dynamically localized when periodic $\delta $-function kicks are applied with a particular strength. We use both numerical and analytical methods to study the effects of interactions in three different models in one dimension. T…

[Phys. Rev. B 95, 014305] Published Fri Jan 13, 2017

]]>The interplay between symmetry and topology is one of the most exciting avenues of modern condensed matter research. Here, the authors propose a new and unified approach for describing the low-energy physics of two-dimensional spin-singlet superconductors, placing them in a class of topologically ordered states akin to quantum Hall fluids and spin liquids. Starting from a microscopic model of two-dimensional paired fermions with a dynamical electromagnetism (that is also confined to two spatial dimensions), the authors derive Chern-Simons theories for all spin-singlet gapped superconductors, including $s$-wave and chiral states. The topological field theories constructed here thus pave the way towards understanding superconductors as symmetry-enriched topological phases of matter.

[Phys. Rev. B 95, 014508] Published Fri Jan 13, 2017

]]>We perform fully coupled numerical simulations of helium II pure superflows in a channel, with vortex-line density typical of experiments. Peculiar to our model is the computation of the back-reaction of the superfluid vortex motion on the normal fluid and the presence of solid boundaries. We recove…

[Phys. Rev. B 95, 014509] Published Fri Jan 13, 2017

]]>In the framework of the microscopic Bogoliubov-de Gennes theory, we study the topological properties of skyrmionic states under applied magnetic flux in mesoscopic symmetric and asymmetric $p$-wave superconducting noncircular systems. For a perfect square (rectangular) sample, an enclosed square-loop-…

[Phys. Rev. B 95, 014510] Published Fri Jan 13, 2017

]]>We systematically investigate elastic anharmonic behavior in ferromagnetic body-centered cubic (bcc) Fe and ${\mathrm{Fe}}_{1-x}{M}_{x}$ ($M=\mathrm{Al}$, V, Cr, Co, or Ni) random alloys by means of density-functional simulations. To benchmark computational accuracy, three *ab initio* codes are used to obtain the complete set of sec…

[Phys. Rev. B 95, 024203] Published Fri Jan 13, 2017

]]>Electron-phonon coupling directly determines the stability of cooperative order in solids, including superconductivity, charge, and spin density waves. Therefore, the ability to enhance or reduce electron-phonon coupling by optical driving may open up new possibilities to steer materials' functional…

[Phys. Rev. B 95, 024304] Published Fri Jan 13, 2017

]]>The band-unfolding method is now widely used to calculate the effective band structures of a disordered system from its supercell model. The unfolded band structures are obtained as if the disordered system really has the crystallographic symmetry of its underlying structure. However, it has still been difficult to decompose the unfolded band structures into the modes based on the crystallographic symmetry of the underlying structure. This has prohibited detailed analyses of, e.g., selection rules and avoided band crossings for the unfolded band structures. The authors here develop a procedure to decompose the unfolded band structures according to the small representations (SRs) of the little groups. The decomposition is performed using the projection operators for SRs derived from the group representation theory. Using this procedure, the authors investigate the phonon band structure of disordered face-centered-cubic Cu${}_{0.75}$Au${}_{0.25}$, which has large variations of atomic masses and force constants among the atomic sites due to the chemical disorder. In the unfolded phonon band structure, several peculiar behaviors such as discontinuous and split branches are found in the decomposed modes corresponding to specific SRs.

[Phys. Rev. B 95, 024305] Published Fri Jan 13, 2017

]]>We use the functional renormalization group (FRG) to derive analytical expressions for thermodynamic observables (density, pressure, entropy, and compressibility) as well as for single-particle properties (wave-function renormalization and effective mass) of interacting bosons in two dimensions as a…

[Phys. Rev. B 95, 024414] Published Fri Jan 13, 2017

]]>The interesting physics and potential memory technologies resulting from topologically protected spin textures such as skyrmions have prompted efforts to discover new material systems that can host these kinds of magnetic structures. Here, we use the highly tunable magnetic properties of amorphous F…

[Phys. Rev. B 95, 024415] Published Fri Jan 13, 2017

]]>Selected universal experimental properties of high-temperature superconducting (HTS) cuprates have been singled out in the last decade. One of the pivotal challenges in this field is the designation of a consistent interpretation framework within which we can describe quantitatively the universal fe…

[Phys. Rev. B 95, 024506] Published Fri Jan 13, 2017

]]>The Gutzwiller wave-function solution of the $t-J-U$ model is considered for the bilayer high-${T}_{C}$ superconductor by using the so-called diagrammatic expansion method. The focus is on the influence of the interlayer effects on the superconducting state. The chosen pairing symmetry is a mixture of ${d}_{{x}^{2}-{y}^{2}}$…

[Phys. Rev. B 95, 024507] Published Fri Jan 13, 2017

]]>We present analytical and numerical results regarding the magnetization full counting statistics (FCS) of a subsystem in the ground state of the Haldane-Shastry chain. Exact Pfaffian expressions are derived for the cumulant generating function, as well as any observable diagonal in the spin basis. I…

[Phys. Rev. B 95, 035119] Published Fri Jan 13, 2017

]]>Ensemble density functional theory (eDFT) is an exact time-independent alternative to time-dependent DFT (TD-DFT) for the calculation of excitation energies. Despite its formal simplicity and advantages in contrast to TD-DFT (multiple excitations, for example, can be easily taken into account in an …

[Phys. Rev. B 95, 035120] Published Fri Jan 13, 2017

]]>Which is the best single-particle basis to express a Hubbard-like lattice model? A rigorous variational answer to this question leads to equations the solution of which depends in a self-consistent manner on the lattice ground state. Contrary to naive expectations, for arbitrary small interactions, …

[Phys. Rev. B 95, 035121] Published Fri Jan 13, 2017

]]>We introduce an equilibrium formulation of the functional renormalization group (fRG) for inhomogeneous systems capable of dealing with spatially finite-ranged interactions. In the general third-order truncated form of fRG, the dependence of the two-particle vertex is described by $\mathcal{O}\left({N}^{4}\right)$ independent …

[Phys. Rev. B 95, 035122] Published Fri Jan 13, 2017

]]>We report on electrical spin injection from (Ga,Mn)As into a high-mobility two-dimensional electron gas confined at an (Al,Ga)As/GaAs interface. Besides standard nonlocal electrical detection, we use a magneto-optical approach which provides cross-sectional images of the spin accumulation at the cle…

[Phys. Rev. B 95, 035304] Published Fri Jan 13, 2017

]]>Clean topological insulators exposed to a magnetic field develop Landau levels accompanied by a nonzero Hall conductivity for the infinite slab geometry. In this work we consider the case of disordered topological insulator nanowires and find, in contrast, that a zero Hall plateau emerges within a b…

[Phys. Rev. B 95, 035415] Published Fri Jan 13, 2017

]]>The discovery of topological matter should be an opportunity for revolutionizing electronic devices. Nevertheless, for all their unique properties, to date there are limited feasible devices or applications based on topological materials. The work here recognizes that topological Weyl semimetal materials, through their protected gap closing and spin-orbit locking, could be used to detect low-frequency infrared radiation. Detecting infrared light electrically beyond a ten-micron wavelength is rather difficult with few ready made commercial solutions. The authors find that Weyl semimetals could provide an ideal solution for detecting mid- and far-infrared light even at room temperature. In this work, they describe the conditions of the materials to be effective photodetectors (noncentrosymmetry, doping levels etc.) and provide a detailed analysis of this photovoltaic effect.

[Phys. Rev. B 95, 041104(R)] Published Fri Jan 13, 2017

]]>We discuss in detail algorithms for implementing tensor network renormalization (TNR) for the study of classical statistical and quantum many-body systems. First, we recall established techniques for how the partition function of a $2D$ classical many-body system or the Euclidean path integral of a $1D$…

[Phys. Rev. B 95, 045117] Published Fri Jan 13, 2017

]]>We introduce an effective theory with manifest particle-vortex symmetry for disordered thin films undergoing a magnetic field-tuned superconductor-insulator transition. The theory may enable one to access both the critical properties of the strong-disorder limit, which has recently been confirmed by…

[Phys. Rev. B 95, 045118] Published Fri Jan 13, 2017

]]>We investigate the gap in the single-electron spectrum of twisted bilayer graphene. In a perfect infinite lattice of a twisted bilayer, the gap varies exponentially in response to weak changes of the twist angle. Such a large sensitivity makes theoretical predictions of the gap nearly impossible, si…

[Phys. Rev. B 95, 045119] Published Fri Jan 13, 2017

]]>The doping of semiconductors with magnetic impurities gives rise not only to a spin-spin interaction between quasifree carriers and magnetic impurities but also to a local spin-independent disorder potential for the carriers. Based on a quantum kinetic theory for the carrier and impurity density mat…

[Phys. Rev. B 95, 045204] Published Fri Jan 13, 2017

]]>Photoinduced magnetic polarons in EuTe, with a magnetic moment of several hundred Bohr magnetons, were investigated as a function of pump intensity and temperature by pump-probe Faraday rotation. The quantum efficiency for optical generation of magnetic polarons is found to be 0.09. The pump-intensi…

[Phys. Rev. B 95, 045205] Published Fri Jan 13, 2017

]]>We present experimental results on the light-to-sound transduction by a superlattice embedded in an optical microcavity, using picosecond ultrasonics. Experiments on the ability to generate and detect phonons at 0.3 and 0.6 THz were performed at low temperature. Finally, we demonstrate that such a d…

[Phys. Rev. B 95, 014304] Published Thu Jan 12, 2017

]]>Using novel instrumentation to combine extreme conditions of intense pulsed magnetic field up to 60 T and high pressure up to 4 GPa, we have established the three-dimensional (3D) magnetic field-pressure-temperature phase diagram of a pure stoichiometric heavy-fermion antiferromagnet (${\mathrm{CeRh}}_{2}{\mathrm{Si}}_{2}$). We …

[Phys. Rev. B 95, 014411] Published Thu Jan 12, 2017

]]>Using a simple numerical model of skyrmions in a two-dimensional system interacting with a quasi-one-dimensional periodic substrate under combined dc and ac drives where the dc drive is applied perpendicular to the substrate periodicity, we show that a rich variety of novel phase-locking dynamics ca…

[Phys. Rev. B 95, 014412] Published Thu Jan 12, 2017

]]>By using the spin pumping process, we show that it is possible to transport a pure spin current across layers of conducting polyaniline (PANI) with several hundred nanometers sandwiched between a film of the ferrimagnetic insulator yttrium iron garnet (YIG) and a thin layer of platinum. The spin cur…

[Phys. Rev. B 95, 014413] Published Thu Jan 12, 2017

]]>In pulsed magnetic fields up to 65 T and at temperatures below the Néel transition, our magnetization and magnetostriction measurements reveal a field-induced metamagneticlike transition that is suggestive of an antiferromagnetic to ferrimagnetic ordering. Our data also suggest a change in the natur…

[Phys. Rev. B 95, 014414] Published Thu Jan 12, 2017

]]>The authors present a systematic density functional theory GGA characterization of the ${R}_{4}$Fe${}_{2}$As${}_{2}$Te${}_{1-x}$O${}_{4-y}$F${}_{y}$ family of compounds (called “42214”) as a function of a set of key tuning parameters: rare earth ($R$ = Pr, Sm, and Gd), Te content, oxygen to fluorine substitutional doping, and external pressure. The analysis is based on an unfolding procedure that allows observation of the behavior of hole and electron pockets of the Fermi surface and of the nesting function. The present study includes characterization of a related hypothetical compound having Se substituting for Te. Results show that this peculiar compound family offers very good opportunities to properly harness material properties. Nesting, Fermi surface (topology and size), and magnetism can be easily modified by changing chemical composition: such tuning may lead to improved superconducting properties.

[Phys. Rev. B 95, 014415] Published Thu Jan 12, 2017

]]>As the temperature lowers in the gapless region, quantum quasi-1D spin systems show one-dimensional (1D) short-range ordering (SRO) corresponding to a Tomonaga-Luttinger liquid (TLL) by the interaction within chains, and then at lower temperatures where the small interchain interaction cannot be ignored, they have a three-dimensional (3D) long- range ordered (LRO, BEC) phase. This generally accepted scenario for the dimensional crossover of quasi-1D spin ordering, however, is debatable around the critical field, because the 1D SRO (TLL) regime has a linear boundary on the $H$-$T$ phase diagram, while the 3D LRO transition temperature has a convex shape. To this dimensionality paradox around the critical field, the authors have given the solution, experimentally by detailed analyses of the specific heat and ac susceptibility for bond-alternating antiferromagnetic chains in pentafluorophenyl nitronyl nitroxide (F${}_{5}$PNN). They reveal the existence of a definite field region near a critical field, where 3D LRO (BEC) directly occurs without passing through 1D SRO region at higher temperatures, even if the interchain interaction is sufficiently small compared to the intrachain one.

[Phys. Rev. B 95, 020408(R)] Published Thu Jan 12, 2017

]]>We examine the ultrafast demagnetization process of iron-based materials, namely, ${\mathrm{Fe}}_{6}$ clusters and bulk bcc Fe, with time-dependent spin-density functional theory (TDSDFT). The magnetization continuity equation is reformulated and the torque due to the spin-current divergence is written in terms of …

[Phys. Rev. B 95, 024412] Published Thu Jan 12, 2017

]]>We have performed first-order reversal curve (FORC) measurements to investigate the irreversible magnetization processes in the low-temperature phase of MnBi. Using temperature-dependent FORC analysis, we are able to provide a clear insight into the effects of microstructural parameters such as grai…

[Phys. Rev. B 95, 024413] Published Thu Jan 12, 2017

]]>Recently, Tao and Mo developed a semilocal exchange-correlation density functional. The exchange part of this functional is derived from a density-matrix expansion corrected to reproduce the fourth-order gradient expansion of the exchange energy in the slowly-varying-density limit, while the correla…

[Phys. Rev. B 95, 035118] Published Thu Jan 12, 2017

]]>Electron transport in small graphene nanoribbons is studied by microwave emulation experiments and tight-binding calculations. In particular, it is investigated under which conditions a transport gap can be observed. Our experiments provide evidence that armchair ribbons of width $3m+2$ with integer $m$…

[Phys. Rev. B 95, 035413] Published Thu Jan 12, 2017

]]>We have studied a generalized three-band crossing model in 2D, the generalized $\alpha -{T}_{3}$ lattice, ranging from the pseudospin-1 Dirac equation through a quadratic+flat band touching to the pseudospin-1/2 Dirac equation. A general method is presented to determine the operator form of the Green's function,…

[Phys. Rev. B 95, 035414] Published Thu Jan 12, 2017

]]>Broken symmetry states in bilayer graphene in perpendicular electric ${E}_{\perp}$ and in-plane magnetic ${B}_{\parallel}$ fields are studied in the presence of the dynamically screened long-range Coulomb interaction and the symmetry-breaking contact four-fermion interactions. The integral gap equations are solved numericall…

[Phys. Rev. B 95, 045410] Published Thu Jan 12, 2017

]]>We consider the spectrum of Andreev bound states (ABSs) in an exemplary four-terminal superconducting structure where four chaotic cavities are connected by quantum point contacts to the terminals and to each other forming a ring. We nickname the resulting device *4T-ring*. Such a tunable device can b…

[Phys. Rev. B 95, 045411] Published Thu Jan 12, 2017

]]>We investigated thermally activated ionization and thermally activated crossover as the two possibilities of quenching of $5d$ luminescence in $\mathrm{P}{\mathrm{r}}^{3+}$-doped ${\mathrm{Y}}_{3}\mathrm{A}{\mathrm{l}}_{5-x}\mathrm{G}{\mathrm{a}}_{x}{\mathrm{O}}_{12}$. Varying the Ga content $x$ gives the control over the relative energy level location of the $5d$ and $4{f}^{2}:{}^{3}P_{J}$ states of $\mathrm{P}{\mathrm{r}}^{3+}$ and the host …

[Phys. Rev. B 95, 014303] Published Wed Jan 11, 2017

]]>Transition metal compounds with the ${\left({t}_{2g}\right)}^{4}$ electronic configuration are expected to be nonmagnetic atomic singlets both in the weakly interacting regime due to spin-orbit coupling, as well as in the Coulomb dominated regime with oppositely aligned $L=1$ and $S=1$ angular momenta. However, starting with …

[Phys. Rev. B 95, 014409] Published Wed Jan 11, 2017

]]>${\mathrm{Fe}}_{2}\mathrm{MnSi}$ exhibits a ferromagnetic transition at ${T}_{C}\sim 230$ K and another transition to a phase with antiferromagnetic components at ${T}_{A}\sim 60$ K. By substituting V for Mn, so as to obtain ${\mathrm{Fe}}_{2}{\mathrm{Mn}}_{1-x}{\mathrm{V}}_{x}\mathrm{Si}$, ${T}_{A}$ is revealed to decrease with $x$ and then vanish around $x\sim 0.2$. In this study, the phase boundary of the tra…

[Phys. Rev. B 95, 014410] Published Wed Jan 11, 2017

]]>The $5d$-transition-metal pyrochlore oxide $\mathrm{C}{\mathrm{d}}_{2}\mathrm{R}{\mathrm{e}}_{2}{\mathrm{O}}_{7}$, which was recently suggested to be a prototype of the spin-orbit-coupled metal [Phys. Rev. Lett. **115**, 026401 (2015)], exhibits an inversion-symmetry-breaking (ISB) transition at 200 K and a subsequent superconductivity below 1 K at ambient pressure.…

[Phys. Rev. B 95, 020102(R)] Published Wed Jan 11, 2017

]]>The linear and nonlinear phononic interactions between an optically excited infrared (IR) or hyper-Raman mode and a driven Raman mode are computed for the ${d}^{0}\left({\mathrm{CaTiO}}_{3}\right)$ and ${d}^{1}\left({\mathrm{LaTiO}}_{3}\right)$ titanates within a first-principles density functional framework. We calculate the potential energy surface expanded …

[Phys. Rev. B 95, 024109] Published Wed Jan 11, 2017

]]>A study of the zero field and field induced magnetic states of the frustrated rare earth tetraboride ${\mathrm{HoB}}_{4}$ has been carried out using single crystal neutron diffraction complemented by magnetization measurements. In zero field, ${\mathrm{HoB}}_{4}$ shows magnetic phase transitions at ${T}_{\mathrm{N}1}=7.1$ K to an incommensurate s…

[Phys. Rev. B 95, 024410] Published Wed Jan 11, 2017

]]>The authors investigate the properties of 378 half-Heusler compounds using density functional theory with the goal of identifying promising candidates for spintronic applications, e.g. half-metals. Although DFT has often been applied to the search for half-metals, this study may be the most comprehensive attempt to identify which of the compounds predicted by DFT to be half-metals are likely to be fabricated. The calculated formation energy of each of the 378 potential half Heuslers was compared to that of all competing phases and combination of phases in the Open Quantum Materials Database. Those semiconductors, half-metals, and near half-metals within an empirically determined 0.1 eV/atom hull distance margin for neglected effects were deemed of interest for further experimental investigation.

[Phys. Rev. B 95, 024411] Published Wed Jan 11, 2017

]]>Nondiagonal couplings to a bosonic bath completely change polaronic dynamics, from the usual diagonally coupled paradigm of smoothly varying properties. We study, using analytic and numerical methods, a model having both diagonal Holstein and nondiagonal Su-Schrieffer-Heeger (SSH) couplings. The cri…

[Phys. Rev. B 95, 035117] Published Wed Jan 11, 2017

]]>The dielectric function is one of the most important quantities that describes the electrical and optical properties of solids. Accurate modeling of the frequency-dependent dielectric function has great significance in the study of the long-range van der Waals (vdW) interaction for solids and adsorp…

[Phys. Rev. B 95, 035203] Published Wed Jan 11, 2017

]]>We present an analytical and numerical investigation of the spectral and transport properties of a quadruple quantum-dot (QQD) structure which is one of the popular low-dimensional systems in the context of fundamental quantum physics study, future electronic applications, and quantum calculations. …

[Phys. Rev. B 95, 035411] Published Wed Jan 11, 2017

]]>The electronic conductance of graphene-based bilayer flake systems reveals different quantum interference effects, such as Fabry-Pérot resonances and sharp Fano antiresonances on account of competing electronic paths through the device. These properties may be exploited to obtain spin-polarized curr…

[Phys. Rev. B 95, 035412] Published Wed Jan 11, 2017

]]>[Phys. Rev. B 95, 039902] Published Wed Jan 11, 2017

]]>The resistivities of the dilute, strongly interacting two-dimensional electron systems in the insulating phase of a silicon MOSFET are the same for unpolarized electrons in the absence of magnetic field and for electrons that are fully spin polarized by the presence of an in-plane magnetic field. In…

[Phys. Rev. B 95, 041301(R)] Published Wed Jan 11, 2017

]]>After more than a decade, direct observation of the odd frequency triplet pairing state in superconducting hybrid structures remains elusive. We propose an experimentally feasible setup that can unambiguously reveal the zero energy peak due to proximity-induced *equal spin* superconducting triplet cor…

[Phys. Rev. B 95, 045115] Published Wed Jan 11, 2017

]]>We perform a magnetoinfrared spectroscopy study of the semiconductor to semimetal transition of InAs/GaSb double quantum wells from the normal to the inverted state. We show that owing to the low carrier density of our samples, the magnetoabsorption spectra evolve from a single cyclotron resonance p…

[Phys. Rev. B 95, 045116] Published Wed Jan 11, 2017

]]>In spite of their relatively high lattice thermal conductivity ${\kappa}_{\ell}$, the $X\mathrm{NiSn}$ ($X=\text{Ti}$, Zr, or Hf) half-Heusler compounds are good thermoelectric materials. Previous studies have shown that ${\kappa}_{\ell}$ can be reduced by sublattice alloying on the $X$ site. To cast light on how the alloy composition affects ${\kappa}_{\ell}$, we …

[Phys. Rev. B 95, 045202] Published Wed Jan 11, 2017

]]>We report magnetic susceptibility, electrical conductivity and optical absorption of ${\mathrm{Ce}}_{1-x}{M}_{x}{\mathrm{O}}_{2}$ where $M$ = Nb,Ta and $0\le x\le 0.03$. The dc conductivity follows a simple thermally activated Arrhenius-type behavior in the $T=70$–700 K range with a change in slope at ${T}^{*}\approx 155$ K. The high-temperature activation en…

[Phys. Rev. B 95, 045203] Published Wed Jan 11, 2017

]]>The magnetic-field dependence of the energy spectrum, wave function, binding energy, and oscillator strength of exciton states confined in a circular graphene quantum dot (CGQD) is obtained within the configuration interaction method. We predict that (i) excitonic effects are very significant in the…

[Phys. Rev. B 95, 045409] Published Wed Jan 11, 2017

]]>The impact of flexoelectric coupling on polarization reversal and space-charge variation in thin films of ferroelectric semiconductors has been studied theoretically. The relaxation-type Landau-Khalatnikov equation together with the Poisson equation and the theory of elasticity equations have been u…

[Phys. Rev. B 95, 014104] Published Tue Jan 10, 2017

]]>Materials physicists are increasingly coming to understand that domain walls in complex materials often have a life of their own. Far from being unwanted “defects”, they may have rich and interesting physics not available in the bulk material. Here, the authors use first-principles theoretical methods to consider ferroelectric domain walls in a promising family of corundum-derivative materials. Beyond studying issues of domain wall mobility and clarifying the factors that allow polarization reversal, the authors also identify an unusual set of domain-wall-specific couplings between polarization, magnetization, and chirality that they suggest may lead to new functionalities.

[Phys. Rev. B 95, 014105] Published Tue Jan 10, 2017

]]>Local aspects of magnetism of disordered FePt are investigated by *ab initio* fully relativistic full-potential calculations, employing the supercell approach and the coherent potential approximation (CPA). The focus is on trends of the spin and orbital magnetic moments with chemical composition and w…

[Phys. Rev. B 95, 014408] Published Tue Jan 10, 2017

]]>We present a theory of optical conductivity in systems with finite-momentum Cooper pairs. In contrast to the BCS pairing where ac conductivity is purely imaginary in the clean limit, there is nonzero ac absorption across the superconducting gap for finite-momentum pairing if we break the Galilean sy…

[Phys. Rev. B 95, 014506] Published Tue Jan 10, 2017

]]>Extreme magnetoresistance (XMR) in topological semimetals is a recent discovery which attracts attention due to its robust appearance in a growing number of materials. To search for a relation between XMR and superconductivity, we study the effect of pressure on LaBi. By increasing pressure, we obse…

[Phys. Rev. B 95, 014507] Published Tue Jan 10, 2017

]]>We investigated surface acoustic wave propagation in a Ni/${\mathrm{LiNbO}}_{3}$ hybrid device. We found that the absorption and phase velocity are dependent on the sign of the wave vector, which indicates that the surface acoustic wave propagation has nonreciprocal characteristics induced by simultaneous breaking …

[Phys. Rev. B 95, 020407(R)] Published Tue Jan 10, 2017

]]>Two quaternary Heusler alloys, equiatomic CuNiMnAl and CuNiMnSn, are studied using density functional theory to understand their tendency for atomic disorder on the lattice and the magnetic effects of disorder. Disordered structures with antisite defects of atoms of the same and different sublattice…

[Phys. Rev. B 95, 024108] Published Tue Jan 10, 2017

]]>We theoretically study the response of a many-body localized system to a local quench from a quantum information perspective. We find that the local quench triggers entanglement growth throughout the whole system, giving rise to a logarithmic lightcone. This saturates the modified Lieb-Robinson boun…

[Phys. Rev. B 95, 024202] Published Tue Jan 10, 2017

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