Extraordinary electronic phases can form in artificial oxide heterostructures, which will provide a fertile ground for new physics and also give rise to novel device functions. Based on a systematic first-principles density functional theory study of the magnetic and electronic properties of the (11…

[Phys. Rev. B 95, 134448] Published Fri Apr 28, 2017

]]>We investigate from first principles the fieldlike spin-orbit torques (SOTs) in a ${\mathrm{Ag}}_{2}\mathrm{Bi}$-terminated Ag(111) film grown on ferromagnetic Fe(110). We find that a large part of the SOT arises from the spin-orbit interaction (SOI) in the ${\mathrm{Ag}}_{2}\mathrm{Bi}$ layer far away from the Fe layers. These results clearly hint…

[Phys. Rev. B 95, 134449] Published Fri Apr 28, 2017

]]>A symmetry broken phase of a system with internal degrees of freedom often features a complex order parameter, which generates a rich variety of topological excitations and imposes topological constraints on their interaction (topological influence); yet the very complexity of the order parameter ma…

[Phys. Rev. B 95, 134520] Published Fri Apr 28, 2017

]]>We investigate the connection between local structure and dynamics in the liquid and undercooled $\mathrm{A}{\mathrm{l}}_{93}\mathrm{C}{\mathrm{r}}_{7}$ alloy using *ab initio* molecular dynamics simulations. In the liquid phase, we show the striking effects of Cr alloying on the atomic-scale structure, characterized by a heterogeneous local orderi…

[Phys. Rev. B 95, 144210] Published Fri Apr 28, 2017

]]>For metallic glasses, “flexibility volume” has recently been introduced as a property-revealing indicator of the structural state the glass is in. This parameter incorporates the atomic volume and the vibrational mean-square displacement, to combine both static structure and dynamics information. Fl…

[Phys. Rev. B 95, 144211] Published Fri Apr 28, 2017

]]>We show that the application of circularly polarized electromagnetic radiation on the surface of a Weyl semimetal can generate states at that surface. These states can be characterized by their surface momentum. The Floquet eigenvalues ${e}^{i\theta}$ of these states come in complex conjugate pairs rather than …

[Phys. Rev. B 95, 144311] Published Fri Apr 28, 2017

]]>Chiral magnetism plays an increasingly important role in condensed matter investigations driven by the discovery of exotic spin textures, such as the topologically protected chiral skyrmions that can form a lattice under magnetic fields. The nature and universality of the phase diagram in cubic chiral magnets has been the subject of numerous experimental and theoretical investigations, including the transition to the helimagnetic state. In MnSi, the archetypal system in this family, this transition is of first order and involves a precursor phase, where strong chiral fluctuating correlations build up. This work presents an experimental investigation of the structural and dynamical aspects of the phase transition in Fe${}_{1-x}$Co${}_{x}$Si, a system that belongs to the same family as MnSi but with the additional possibility to tune important physical interactions and parameters through variation of the Fe and Co concentration. In this system, the combination of small-angle neutron scattering and neutron spin echo spectroscopy uncovers that the scenario of the transition is qualitatively very different from that in MnSi. This goes beyond what can be expected from a comparison of the relevant length scales and thus challenges the validity of a universal approach to the helimagnetic transition in cubic chiral magnets.

[Phys. Rev. B 95, 144433] Published Fri Apr 28, 2017

]]>We examine the possibility of using graphene nanoribbons (GNRs) with directly substituted chromium atoms as a spintronic device. Using density functional theory, we simulate a voltage bias across a constructed GNR in a device setup where a magnetic dimer has been substituted into the lattice. Throug…

[Phys. Rev. B 95, 155450] Published Fri Apr 28, 2017

]]>Given recent progress in the realization of Majorana zero modes in semiconducting nanowires with proximity-induced superconductivity, a crucial next step is to attempt an experimental demonstration of the predicted braiding statistics associated with the Majorana mode. Such a demonstration should, i…

[Phys. Rev. B 95, 155451] Published Fri Apr 28, 2017

]]>We present a general framework for studying strongly coupled radiative and conductive heat transfer between arbitrarily shaped bodies separated by subwavelength distances. Our formulation is based on a macroscopic approach that couples our recent fluctuating volume-current (FVC) method of near-field…

[Phys. Rev. B 95, 161409(R)] Published Fri Apr 28, 2017

]]>Wrinkles and blisters of graphene on Ir(111) give rise to remarkably high signals in inelastic electron tunneling spectroscopy due to graphene phonons. Spatially resolved spectra unravel the gradual increase of the graphene phonon signatures with progressive delamination of graphene from the metal s…

[Phys. Rev. B 95, 161410(R)] Published Fri Apr 28, 2017

]]>Anisotropic charge-carrier transport in black phosphorus limited by ionized impurity scattering at finite temperature is explored theoretically. The anisotropic electronic structure enters the calculation for the polarizability (screening), the momentum relaxation time, and the mobility. For finite …

[Phys. Rev. B 95, 165446] Published Fri Apr 28, 2017

]]>Doping plays a key role in modulating electronic properties of 2D semiconductors, and thus is vitally important for next-generation nanoelectronics and optoelectronics devices. However, how to effectively tune the dopant ionization energy (IE) so as to achieve robust and controllable $n$-type or $p$-typ…

[Phys. Rev. B 95, 165447] Published Fri Apr 28, 2017

]]>We present a study of the compositional and temperature-dependent magnetic properties of epitaxial CoCr thin films whose composition has a bathtublike depth profile $\mathrm{Co}/\mathrm{C}{\mathrm{o}}_{1\to 1\text{\u2212}{x}_{\mathrm{c}}}\mathrm{C}{\mathrm{r}}_{0\to {x}_{\mathrm{c}}}/\mathrm{C}{\mathrm{o}}_{1\text{\u2212}{x}_{\mathrm{c}}}\mathrm{C}{\mathrm{r}}_{{x}_{\mathrm{c}}}/\mathrm{C}{\mathrm{o}}_{1\text{\u2212}{x}_{\mathrm{c}}\to 1}\mathrm{C}{\mathrm{r}}_{{x}_{\mathrm{c}}\to 0}/\mathrm{Co}$ with the highest Cr concentration $\left({x}_{\mathrm{c}}\right)$ at the center of the sample. Polarized neutron re…

[Phys. Rev. B 95, 134445] Published Thu Apr 27, 2017

]]>We report on the magnetic properties of Co clusters (around 2.5 nm diameter) embedded in different matrices (C, Au, and Cu). Firstly, we accurately determine the intrinsic magnetic properties of the particles, using highly diluted samples where no interactions are detected, and a procedure relying o…

[Phys. Rev. B 95, 134446] Published Thu Apr 27, 2017

]]>We address the theory of the coupled lattice and magnetization dynamics of freely suspended single-domain nanoparticles. Magnetic anisotropy generates low-frequency satellite peaks in the microwave absorption spectrum and a blueshift of the ferromagnetic resonance (FMR) frequency. The low-frequency …

[Phys. Rev. B 95, 134447] Published Thu Apr 27, 2017

]]>We report measurements of the in-plane London penetration depth $\lambda $ in single crystals of the $\alpha -{\mathrm{PdBi}}_{2}$ superconductor—the $\alpha $-phase counterpart of the putative topological superconductor $\beta -{\mathrm{PdBi}}_{2}$, down to 0.35 K using a high-resolution tunnel-diode-based technique. Both $\lambda $ and superfluid density ${\rho}_{s}$ exhibit…

[Phys. Rev. B 95, 134519] Published Thu Apr 27, 2017

]]>We study impurity scattering in the normal and $d$-wave superconducting states of line nodal semimetals and show that, due to additional scattering phase space available for impurities on the surface, the quasiparticle interference pattern acquires an extended character instead of a discrete collectio…

[Phys. Rev. B 95, 140202(R)] Published Thu Apr 27, 2017

]]>The strong spin-spin exchange interaction in some low-dimensional magnetic materials can give rise to a high group velocity and thermal conductivity contribution from magnons, which are energy quanta of collective spin excitations. Examples are the incommensurate layered compounds (Sr,Ca,La)${}_{14}$Cu${}_{24}$O${}_{41}$, with strong antiferromagnetic interaction along the ladders. The effects of grain boundaries and defects on quasi-one-dimensional magnon transport in these compounds are not well understood. Here, the authors report the microstructures and anisotropic thermal transport properties of textured Sr${}_{14}$Cu${}_{24}$O${}_{41}$. TEM clearly reveals nanolayered grains and the presence of dislocations and planar defects. The thermal conductivity contribution and mean free paths of magnons in the textured samples are evaluated with the use of a kinetic model for one-dimensional magnon transport, and found to be suppressed significantly compared to single crystals at low temperatures. The experimental results can be explained by a one-dimensional magnon-defect scattering model, provided that the magnon–grain boundary scattering mean free path in the anisotropic magnetic structure is smaller than the average length of these nanolayers along the $c$ axis. The finding suggests low transmission coefficients for energy-carrying magnons across grain boundaries.

[Phys. Rev. B 95, 144310] Published Thu Apr 27, 2017

]]>We have carried out a Schrieffer-Wolff transformation on a general tight-binding Hamiltonian and obtained a $4f$-one-band effective Hubbard Hamiltonian to study the physical origin of ferromagnetism in ${\mathrm{CeO}}_{2-\delta}$ nanoparticle systems. For a low temperature regime and low concentrations of oxygen vacancies…

[Phys. Rev. B 95, 144430] Published Thu Apr 27, 2017

]]>The magnetic domains in a magnetic shape-memory Ni-Mn-Ga alloy were observed by magneto-optical Kerr microscopy using monochromatic blue LED light. The domains were observed for both single- and multivariant ferroelastic states of modulated martensite. The multivariant state with very fine twins was…

[Phys. Rev. B 95, 144431] Published Thu Apr 27, 2017

]]>Recently, it was suggested that metastable spin supercurrents (spin superfluidity) are possible in the magnon condensate observed in yttrium iron garnet (YIG) magnetic films under strong magnon pumping. In YIG, magnetic anisotropy is rather weak, and this material can be treated as an isotropic ferromagnet. Its order-parameter space is a sphere of radius equal to the spontaneous magnetization $M$. A current state maps on the equatorial circumference on the sphere, and topology of the sphere allows us to continuously transform the equatorial circumference to the point. This rules out metastable current states. Only easy-plane anisotropy reducing the order-parameter space from the sphere to the equatorial circumference makes current states topologically stable. However, by pumping magnons to the isotropic ferromagnet in a magnetic field, it is possible to support a strongly nonequilibrium state with fixed average ${M}_{z}$. This confines the precessing spin to an “easy plane” of dynamical rather than topological origin and makes metastable spin currents possible. But final judgment requires evaluation of the Landau superfluidity criterion as done in the present work. The conclusion is that spin superfluidity in YIG films is possible in principle, although the recently published claim of its observation is not justified.

[Phys. Rev. B 95, 144432] Published Thu Apr 27, 2017

]]>We calculate the optical conductivity $\sigma (T,\mathrm{\Omega})$ of a gas of Bogoliubov quasiparticles from their Green's function and the Kubo formula. We make comparisons with corresponding normal-state and superconducting-state results. The superconducting case includes the dynamic response of the condensate through…

[Phys. Rev. B 95, 144516] Published Thu Apr 27, 2017

]]>The quasiskutterudite superconductors ${A}_{3}{T}_{4}{\mathrm{Sn}}_{13}$ ($A=\text{Sr}$, Ca; $T=\text{Ir}$, Rh, Co) are highly tunable, featuring a structural quantum critical point. We construct a temperature-lattice constant phase diagram for these isovalent compounds, establishing ${\mathrm{Ca}}_{3}{\mathrm{Rh}}_{4}{\mathrm{Sn}}_{13}$ and ${\mathrm{Ca}}_{3}{\mathrm{Co}}_{4}{\mathrm{Sn}}_{13}$ as members close to and far away …

[Phys. Rev. B 95, 155142] Published Thu Apr 27, 2017

]]>Transport measurements under tilted magnetic fields were performed on a series of C-doped (001) GaAs/AlGaAs two-dimensional hole quantum wells. Due to a large $g$ factor, Zeeman energy is large and comparable to the cyclotron energy in these samples. On the other hand, it was found that the in-plane c…

[Phys. Rev. B 95, 155316] Published Thu Apr 27, 2017

]]>General expressions for the electron- and hole-acoustic-phonon deformation potential Hamiltonians $\left({H}_{\text{E-DP}}\right)$ are derived for the case of Ge/Si and Si/Ge core/shell nanowire structures (NWs) with circular cross section. Based on the short-range elastic continuum approach and on derived analytical result…

[Phys. Rev. B 95, 155317] Published Thu Apr 27, 2017

]]>We investigate the influence of spatial dispersion on atom-surface quantum friction. We show that for atom-surface separations shorter than the carrier's mean free path within the material, the frictional force can be several orders of magnitude larger than that predicted by local optics. In additio…

[Phys. Rev. B 95, 155448] Published Thu Apr 27, 2017

]]>We discuss the emergence of zero-energy Majorana modes in a disordered finite-length $p$-wave one-dimensional superconducting ring, pierced by a magnetic flux $\mathrm{\Phi}$ tuned at an appropriate value $\mathrm{\Phi}={\mathrm{\Phi}}_{*}$. In the absence of fermion parity conservation, we evidence the emergence of the Majorana modes by looking…

[Phys. Rev. B 95, 155449] Published Thu Apr 27, 2017

]]>The tenfold way classification of noninteracting topological insulators represents a great success towards understanding topological states of matter. The question the authors try to address is: can all possible topological insulators be represented by the prototypes in the tenfold way classification (perhaps enriched with some extra symmetries), or are there exceptions fundamentally different from those prototypes? The Hopf insulator was considered as a special type of TI that is not obviously represented by any prototype in the tenfold way classification, but its stability and classification were never clarified. In this work, the authors identify a generalized particle-hole symmetry that gives the Hopf insulator and its higher-dimensional analog a rigorous definition and classification. Moreover, they provide a very heuristic understanding of the minimal models for the 3$d$ and 4$d$ Hopf insulators, based on which possible experimental realization of a Hopf insulator can be found.

[Phys. Rev. B 95, 161116(R)] Published Thu Apr 27, 2017

]]>The electronic structure of $\alpha $-Sn (001) thin films strained compressively in-plane was studied both experimentally and theoretically. A new topological surface state (TSS) located entirely within the gapless projected bulk bands is revealed by *ab initio*-based tight-binding calculations as well as dir…

[Phys. Rev. B 95, 161117(R)] Published Thu Apr 27, 2017

]]>We report on the electronic band structure, structural, magnetic, and thermal properties of ${\mathrm{Ce}}_{2}{\mathrm{Rh}}_{3}{\mathrm{Sn}}_{5}$. Ce ${L}_{\mathrm{III}}$-edge XAS spectra give direct evidence for an intermediate valence behavior. Thermodynamic measurements reveal magnetic transitions at ${T}_{\mathrm{N}1}\approx 2.9$ K and ${T}_{\mathrm{N}2}\approx 2.4$ K. Electrical resistivity shows b…

[Phys. Rev. B 95, 165142] Published Thu Apr 27, 2017

]]>Dark excitons (DEs) confined in epitaxial quantum dots (QDs) are interesting because of their long lifetime compared to bright excitons (BEs). For the same reason they are usually difficult to access in optical experiments. Here we report on the observation of vertically polarized light emission fro…

[Phys. Rev. B 95, 165304] Published Thu Apr 27, 2017

]]>Recent research suggests that the supercritical state consists of liquidlike and gaslike states where particle dynamics and key system properties are qualitatively different. We report experimental evidence of the structural crossover in supercritical neon at pressure and temperature conditions sign…

[Phys. Rev. B 95, 134114] Published Wed Apr 26, 2017

]]>The structural and dynamical properties of FePt nanoparticles were studied within the density functional theory. The effect of size and chemical composition on the dynamical stability of nanoparticles was investigated for the cuboctahedral and icosahedral symmetries. In cuboctahedra, a structural di…

[Phys. Rev. B 95, 134303] Published Wed Apr 26, 2017

]]>The impact of the longitudinal spin Seebeck effect (LSSE) on the magnon damping in magnetic-insulator/nonmagnetic-metal bilayers was recently discussed in several reports. However, results of those experiments can be blurred by multimode excitation within the measured linewidth. In order to avoid po…

[Phys. Rev. B 95, 134441] Published Wed Apr 26, 2017

]]>The field-driven magnetization dynamics of a multiskyrmion cluster in a nanodisk is investigated by micromagnetic simulation and analytical calculation. Under a weak in-plane static magnetic field, the multiskyrmion cluster shows an oscillatory motion around an equilibrium position, which resembles …

[Phys. Rev. B 95, 134442] Published Wed Apr 26, 2017

]]>We report cryogenic magnetic force microscopy (MFM) studies of a 200-nm-thick hexagonal ($h$) ${\mathrm{LuFeO}}_{3}$ film grown by molecular-beam epitaxy on a (111)-oriented yttria-stabilized cubic-zirconia substrate. Labyrinthlike domains $\sim 1.8\phantom{\rule{0.28em}{0ex}}\mu \mathrm{m}$ in size were observed after zero-field cooling below the Néel temperatu…

[Phys. Rev. B 95, 134443] Published Wed Apr 26, 2017

]]>The mutual interaction between the different eigenmodes of a spin-torque oscillator can lead to a large variety of physical mechanisms from mode hopping to multimode generation, that usually reduce their performances as radio-frequency devices. To tackle this issue for the future applications, we in…

[Phys. Rev. B 95, 134444] Published Wed Apr 26, 2017

]]>The superconducting and normal-state properties of the filled-skutterudite system ${\mathrm{Pr}}_{1-x}{\mathrm{Eu}}_{x}{\mathrm{Pt}}_{4}{\mathrm{Ge}}_{12}$ were studied. Polycrystalline samples were investigated via x-ray diffraction, electrical resistivity, magnetic susceptibility, and specific-heat measurements. Upon Eu substitution, we observed a crosso…

[Phys. Rev. B 95, 134517] Published Wed Apr 26, 2017

]]>We calculate the admittance of two types of Josephson weak links—the first is a one-dimensional superconducting wire with a local suppression of the order parameter, and the second is a short S-c-S structure, where S denotes a superconducting reservoir and c is a constriction. The systems of the fir…

[Phys. Rev. B 95, 134518] Published Wed Apr 26, 2017

]]>We suggest a class of two-dimensional lattice spin Hamiltonians describing non-Abelian SU(2) chiral spin liquids—spin analogs of fractional non-Abelian quantum Hall states—with gapped bulk and gapless chiral edge excitations described by the SU(2)${}_{n}$ Wess-Zumino-Novikov-Witten conformal field theory. …

[Phys. Rev. B 95, 140406(R)] Published Wed Apr 26, 2017

]]>The equation of state (EOS) of carbon in its high-pressure solid and liquid phases is of interest to planetary astrophysics and inertial confinement fusion. Of particular interest are the high-pressure shock and release responses of diamond as these provide rigorous constraints on important paths th…

[Phys. Rev. B 95, 144114] Published Wed Apr 26, 2017

]]>We study the quantum melting of stripe phases in models with competing short-range and long-range interactions decaying with distance as $1/{r}^{\sigma}$ in two space dimensions. At zero temperature we find a two step disordering of the stripe phases with the growth of quantum fluctuations. A quantum critical p…

[Phys. Rev. B 95, 144209] Published Wed Apr 26, 2017

]]>We show that the peculiarities of the electron band structure strongly affect the spin-valve effect in heterostructures consisting of a superconductor (S) and two ferromagnetic layers ${\mathrm{F}}_{1}$ and ${\mathrm{F}}_{2}$. For the $\mathrm{S}/{\mathrm{F}}_{1}/{\mathrm{F}}_{2}$ systems the energy shift between the electron bands in the S and ${\mathrm{F}}_{2}$ layers determines whe…

[Phys. Rev. B 95, 144514] Published Wed Apr 26, 2017

]]>We study Andreev reflection and the Josephson effect in a ballistic monolayer of black phosphorous, known as phosphorene. Due to the anisotropic band structure of this system, the supercurrent changes with an order of magnitude when comparing tunneling along two perpendicular directions in the monol…

[Phys. Rev. B 95, 144515] Published Wed Apr 26, 2017

]]>The temperature-dependent electronic structure of the heavy-fermion compound ${\mathrm{CeB}}_{6}$ was investigated thoroughly by means of the combination of density functional theory and single-site dynamical mean-field theory. The band structure, density of states, and $4f$ valence state fluctuation of ${\mathrm{CeB}}_{6}$ were cal…

[Phys. Rev. B 95, 155140] Published Wed Apr 26, 2017

]]>We study numerically the reflectivity of three-dimensional (3D) photonic crystals with a complete 3D photonic band gap. We employ the finite element method to study crystals with the cubic diamondlike inverse woodpile structure. The high-index backbone has a dielectric function similar to silicon. W…

[Phys. Rev. B 95, 155141] Published Wed Apr 26, 2017

]]>Optical pump-THz probe spectroscopy is used to investigate the exciton formation dynamics and its intensity dependence in bulk Ge. Associated with the intraexcitonic $1s\text{\u2212}2p$ transition, the gradual buildup of an absorption peak around 3.1 meV (0.75 THz) signifies a delayed exciton formation after opti…

[Phys. Rev. B 95, 155207] Published Wed Apr 26, 2017

]]>Large room-temperature magnetoresistance observed for devices composed of self-assembled monolayers of different oligophenylene thiols sandwiched between gold contacts has recently been reported [Z. Xie, S. Shi, F. Liu, D. L. Smith, P. P. Ruden, and C. D. Frisbie, ACS Nano **10**, 8571 (2016)]. The tran…

[Phys. Rev. B 95, 155315] Published Wed Apr 26, 2017

]]>We calculate the conductances of a three-way junction of spinless Luttinger-liquid wires as functions of bias voltages applied to three independent Fermi-liquid reservoirs. In particular, we consider the setup that is characteristic of a tunneling experiment, in which the strength of electron-electr…

[Phys. Rev. B 95, 155447] Published Wed Apr 26, 2017

]]>We investigate the topological properties of Fibonacci quasicrystals using cavity polaritons. Composite structures made of the concatenation of two Fibonacci sequences allow one to investigate generalized edge states forming in the gaps of the fractal energy spectrum. We employ these generalized edg…

[Phys. Rev. B 95, 161114(R)] Published Wed Apr 26, 2017

]]>Backscattering-immune chiral modes arise along certain line defects in three-dimensional materials. Here, we study the Floquet chiral modes along Floquet topological defects, namely, the defects come entirely from spatial modulations of periodic driving. We define a precise topological invariant tha…

[Phys. Rev. B 95, 161115(R)] Published Wed Apr 26, 2017

]]>Enabling the confinement of light to a scale far below the one of conventional optics, surface plasmon polaritons (SPPs) induced by an electromagnetic field in a metal-dielectric interface supply an ideal system to explore strong quantized light-matter coupling. The fast matter-SPP population exchan…

[Phys. Rev. B 95, 161408(R)] Published Wed Apr 26, 2017

]]>Recently, there has been a surge of interest in effects arising from the interplay between the electron-electron interaction and spin-orbit coupling (SOC). One such effect is a novel type of collective spin excitations (chiral spin waves), which are oscillations of the magnetization that exist even without an external magnetic field. However, a typical experimental setup in a semiconductor heterostructure includes a magnetic field as well as both Rashba and Dresselhaus types of SOC. In this case, the spectrum of chiral spin waves becomes fairly complicated, with some branches running into or splitting off the continuum of spin-flip excitations. The authors show that this complicated physics can be understood by exact mapping of the quantum kinetic equation for a two-dimensional Fermi liquid onto an effective one-dimensional tight-binding model. This mapping is a useful tool that helps us to understand the nature of the collective modes in a Fermi liquid of arbitrary type.

[Phys. Rev. B 95, 165140] Published Wed Apr 26, 2017

]]>The effect of the electron-electron coupling of the Hubbard type on the one-dimensional electron system with the spin-orbit interaction (SOI), caused by the deformation of the elastic subsystem, is studied. As a rule, the electron-electron repulsion suppresses the deformation-induced SOI. In particu…

[Phys. Rev. B 95, 165141] Published Wed Apr 26, 2017

]]>We examine the temperature dependence of the visibility of the excitonic Aharonov-Bohm peak in type-II quantum dots. We obtain a functional temperature dependence that is similar to that determined by transport experiments, namely, with the ${T}^{-1}$ term due to electron-electron collisions and the ${T}^{-3}$ te…

[Phys. Rev. B 95, 165445] Published Wed Apr 26, 2017

]]>I show that a nonequilibrium paraelectric to ferroelectric transition can be transiently induced using midinfrared pulses. This relies on a quartic $l{Q}_{{\mathrm{l}}_{z}}^{2}{Q}_{{\mathrm{h}}_{x}}^{2}$ coupling between the lowest (${Q}_{{\mathrm{l}}_{z}}$) and highest (${Q}_{{\mathrm{h}}_{x}}$) frequency infrared-active phonon modes of a paraelectric material. Density functional calc…

[Phys. Rev. B 95, 134113] Published Tue Apr 25, 2017

]]>We present quantum mechanical calculations of the Gilbert damping constant $\alpha $ in ultrathin ${\mathrm{L}1}_{0}$ ${[\mathrm{Co}/\mathrm{NM}]}_{N}$ superlattices and (001) fcc ${[\mathrm{Co}/\mathrm{NM}]}_{N}$ magnetic multilayers built of cobalt and nonmagnetic metals NM = Cu, Ag, Pd, Pt, and Au. The calculations are performed within a realistic nine-orbital tight-bi…

[Phys. Rev. B 95, 134440] Published Tue Apr 25, 2017

]]>We numerically demonstrate the possibility to manipulate domain walls in magnetoelastic nanostripes by means of uniform mechanical stresses. The symmetry breaking of the magnetic states in unidimensional ferromagnets allows the control of the domain-wall position or velocity in geometrically tailore…

[Phys. Rev. B 95, 140405(R)] Published Tue Apr 25, 2017

]]>We investigate the effect of periodic and disordered distributions of pairing centers in a one-dimensional itinerant system to obtain the microscopic conditions required to achieve an end Majorana mode and the topological phase diagram. Remarkably, the topological invariant can be generally expresse…

[Phys. Rev. B 95, 140506(R)] Published Tue Apr 25, 2017

]]>We investigate the maximum speed at which a driven superfluid can flow through a narrow constriction with a size on the order of the healing length. Considering dissipation via the thermal nucleation of quantized vortices, we calculate the critical velocity for superfluid ${}^{4}\mathrm{He}$ and ultracold atomtroni…

[Phys. Rev. B 95, 140507(R)] Published Tue Apr 25, 2017

]]>The task of finding the smallest energy needed to bring a solid to its onset of mechanical instability arises in many problems in materials science, from the determination of the elasticity limit to the consistent assignment of free energies to mechanically unstable phases. However, unless the space…

[Phys. Rev. B 95, 144113] Published Tue Apr 25, 2017

]]>Angle-resolved photoemission spectroscopy is used to study the scattering rates of charge carriers from the hole pockets near $\mathrm{\Gamma}$ in the iron-based high-${T}_{c}$ hole-doped superconductors ${\mathrm{K}}_{x}{\mathrm{Ba}}_{1-x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$, $x=0.4$, and ${\mathrm{K}}_{x}{\mathrm{Eu}}_{1-x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$, $x=0.55$, and the electron-doped compound $\mathrm{Ba}{\left({\mathrm{Fe}}_{1-x}{\mathrm{Co}}_{x}\right)}_{2}{\mathrm{As}}_{2}$, $x=0.075$. The scatter…

[Phys. Rev. B 95, 144513] Published Tue Apr 25, 2017

]]>The finite-temperature transport properties of FeRh compounds are investigated by first-principles density-functional-theory-based calculations. The focus is on the behavior of the longitudinal resistivity with rising temperature, which exhibits an abrupt decrease at the metamagnetic transition poin…

[Phys. Rev. B 95, 155139] Published Tue Apr 25, 2017

]]>Superradiance is a signature effect in quantum photonics that explains the collective enhancement of emission power by a factor of ${N}^{2}$ when $N$ emitters are placed in subwavelength proximity. Although the effect is inherently transient, successful attempts have been made to sustain it in the steady-sta…

[Phys. Rev. B 95, 155443] Published Tue Apr 25, 2017

]]>A theory for the thermodynamic properties of steps on faceted crystalline surfaces is presented. The formalism leads to the definition of step excess quantities, including an excess step stress that is the step analogy of surface stress. The approach is used to develop a relationship between the tem…

[Phys. Rev. B 95, 155444] Published Tue Apr 25, 2017

]]>We report the observation of two distinct types of magnetoconductance oscillations in six coupled quantum dots (QDs) in the integer quantum Hall regime. By tuning the magnetic field and gate voltage, we find robust conductance peaks and dips on the plateau of one conductance quantum $2{e}^{2}/h$. These fea…

[Phys. Rev. B 95, 155445] Published Tue Apr 25, 2017

]]>The finite-frequency transport properties of a large-spin molecule attached to ferromagnetic contacts are studied theoretically in the Kondo regime. The focus is on the behavior of the dynamical conductance in the linear response regime, which is determined by using the numerical renormalization gro…

[Phys. Rev. B 95, 155446] Published Tue Apr 25, 2017

]]>We report the enthalpy of oxygen vacancy formation in thin films of electron-doped ${\mathrm{SrTiO}}_{3}$, under different degrees of epitaxial stress. We demonstrate that both compressive and tensile strain decrease this energy at a very similar rate and promote the formation of stable doubly ionized oxygen vacanc…

[Phys. Rev. B 95, 165138] Published Tue Apr 25, 2017

]]>Experiments with ultracold fermionic atoms in optical lattices have attracted much interest in condensed matter physics as they serve as a model for electrons in solids. While experiments now allow the observation of nonequilibrium transport processes with single-site resolution, the theoretical description, especially for strongly correlated fermions, remains very challenging. Standard methods, such as the density matrix renormalization group (DMRG) and nonequilibrium Green functions (NEGF), have been primarily applied to one-dimensional systems and weak to moderate coupling, respectively. Here, the authors perform a detailed comparison of DMRG and NEGF and demonstrate that both can be benchmarked against each other. They observe complementary applicability ranges suggesting that a combination of both will allow to substantially expand the range and duration of first-principles quantum dynamics simulations for fermionic lattice systems.

[Phys. Rev. B 95, 165139] Published Tue Apr 25, 2017

]]>Over the past decade, the open frame (“cagey”) structure of $\mathrm{CoS}{\mathrm{b}}_{3}$ skutterudite has invited intensive filling studies with various rare-earth elements for delivering state-of-the-art midtemperature thermoelectric performance. To rationalize previously reported experimental results and provide new ins…

[Phys. Rev. B 95, 165204] Published Tue Apr 25, 2017

]]>We study an exotic state which is localized only at an intersection of edges of a topological material. This “edge-of-edge” state is shown to exist generically. We construct explicitly generic edge-of-edge states in five-dimensional Weyl semimetals and their dimensional reductions, such as four-dime…

[Phys. Rev. B 95, 165443] Published Tue Apr 25, 2017

]]>The search for novel two-dimensional giant Rashba semiconductors is a crucial step in the development of the forthcoming nanospintronic technology. Using first-principles calculations, we study a stable two-dimensional crystal phase of BiSb having buckled honeycomb lattice geometry, which is yet une…

[Phys. Rev. B 95, 165444] Published Tue Apr 25, 2017

]]>Potassium is introduced into the crystalline herringbone structure of pentacene searching for a compound showing metallic electronic transport properties and, hopefully, superconductivity at small enough temperatures. Several possible structures for stoichiometric KPentacene (1:1), ${\mathrm{K}}_{2}\mathrm{Pentacene}$ (2:1)…

[Phys. Rev. B 95, 134112] Published Mon Apr 24, 2017

]]>The magnetization processes of the spin-3/2 antiferromagnet ${\mathrm{LiInCr}}_{4}{\mathrm{O}}_{8}$ comprising a “breathing” pyrochlore lattice, which is an alternating array of small and large tetrahedra, are studied under ultrahigh magnetic fields of up to 130 T using state-of-the-art pulsed magnets. A half magnetization plate…

[Phys. Rev. B 95, 134438] Published Mon Apr 24, 2017

]]>We propose a semiclassical description of the low-energy properties of *quantum spin ice* in the strong Ising limit. Within the framework of a semiclassical, perturbative Villain expansion, that can be truncated at arbitrary order, we give an analytic and quantitative treatment of the deconfining phas…

[Phys. Rev. B 95, 134439] Published Mon Apr 24, 2017

]]>We calculate the spectrum of the Andreev bound states in a one-dimensional superconductor with a strong Rashba spin-orbit coupling. We focus on the fate of the zero-energy Andreev modes in the presence of time reversal symmetry breaking perturbations, both at the boundary and in the bulk. It is show…

[Phys. Rev. B 95, 134514] Published Mon Apr 24, 2017

]]>The use of artificial atoms as an active lasing medium opens a way to construct novel sources of nonclassical radiation. An example is the creation of photon-number squeezed light. Here, we present a design of a laser consisting of multiple Cooper-pair transistors coupled to a microwave resonator. O…

[Phys. Rev. B 95, 134515] Published Mon Apr 24, 2017

]]>We present measurements of superconducting transition temperature, resistivity, magnetoresistivity, and temperature dependence of the upper critical field of ${\mathrm{Ta}}_{4}{\mathrm{Pd}}_{3}{\mathrm{Te}}_{16}$ under pressures up to 16.4 kbar. All measured properties have an anomaly at $\sim 2\u20134$ kbar pressure range; in particular there is a maxi…

[Phys. Rev. B 95, 134516] Published Mon Apr 24, 2017

]]>Rohart *et al.* [Phys. Rev. B **93**, 214412 (2016)] recently reported calculations indicating two mechanisms for the annihilation of a skyrmion in a Co monolayer on Pt(111). The path calculations were based on a method presented in the Supplemental Material of their article. It is pointed out here that t…

[Phys. Rev. B 95, 136401] Published Mon Apr 24, 2017

]]>[Phys. Rev. B 95, 136402] Published Mon Apr 24, 2017

]]>Majorana bound states have been recently observed at the boundaries of one-dimensional topological superconductors. Yet, controlling the localization of the Majorana states, which is essential to the realization of any topological quantum device, is an ongoing challenge. To this end, we introduce a …

[Phys. Rev. B 95, 140504(R)] Published Mon Apr 24, 2017

]]>A newly discovered family of high-${T}_{\mathrm{c}}$ Fe-based superconductors, ${A}_{e}A{\mathrm{Fe}}_{4}{\mathrm{As}}_{4}$ (${A}_{e}=\text{Ca}$, Sr, Eu and $A=\text{K}$, Rb, Cs), offers further opportunities to understand unconventional superconductivity in these materials. In this Rapid Communication, we report on the superconducting and magnetic properties of ${\mathrm{CaKFe}}_{4}{\mathrm{As}}_{4}$…

[Phys. Rev. B 95, 140505(R)] Published Mon Apr 24, 2017

]]>Observations of multiferroicity and giant improper ferroelectricity in ${\mathrm{CaMn}}_{7}{\mathrm{O}}_{12}$ invigorated the research on this material. Delicate structural changes have been reported to cause ferroelectricity in the magnetically ordered state of ${\mathrm{CaMn}}_{7}{\mathrm{O}}_{12}$ as well as high-temperature crystallographic transformatio…

[Phys. Rev. B 95, 144112] Published Mon Apr 24, 2017

]]>Thermal tensor networks constitute an efficient and versatile representation for quantum lattice models at finite temperatures. By Trotter-Suzuki decomposition, one obtains a $D$+1 dimensional TTN for the $D$-dimensional quantum system and then employs efficient renormalizaton group (RG) contractions to…

[Phys. Rev. B 95, 144428] Published Mon Apr 24, 2017

]]>We measured magnetization, specific heat, electron spin resonance, neutron diffraction, and inelastic neutron scattering of ${\mathrm{CrVMoO}}_{7}$ powder. An antiferromagnetically ordered state appears below ${T}_{\mathrm{N}}=26.5\pm 0.8$ K. We consider that the probable spin model for ${\mathrm{CrVMoO}}_{7}$ is an interacting antiferromagnetic spi…

[Phys. Rev. B 95, 144429] Published Mon Apr 24, 2017

]]>The theoretical understanding of the nematic state of iron-based superconductors and especially of FeSe is still a puzzling problem. Although a number of experiments call for a prominent role of local correlations and place iron superconductors at the entrance of a Hund's metal state, the effect of …

[Phys. Rev. B 95, 144511] Published Mon Apr 24, 2017

]]>We discuss thermal transport through a Josephson junction in a time-dependent situation. We write the spectral representation of the heat current pumped by a generic drive. This enables separation of the dissipative and reactive contributions, of which the latter does not contribute to long-time ave…

[Phys. Rev. B 95, 144512] Published Mon Apr 24, 2017

]]>${}^{31}\mathrm{P}$ NMR measurements have been made on polycrystalline samples to study a metal-insulator (MI) transition and magnetic fluctuations in ${\mathrm{Ru}}_{1-x}{\mathrm{Rh}}_{x}\mathrm{P}$ which has metallic (M), pseudogap (PG), insulating (I), and superconducting (SC) phases. We find that RuP undergoes a crossover from the high-temperature (…

[Phys. Rev. B 95, 155137] Published Mon Apr 24, 2017

]]>We investigated the evolution of magnetism in the $\mathrm{UI}{\mathrm{r}}_{1-x}\mathrm{R}{\mathrm{h}}_{x}\mathrm{Ge}$ system by the systematic study of high-quality single crystals. Lattice parameters of both parent compounds are very similar, resulting in almost identical nearest interatomic uranium distances close to the Hill limit. We established the $\dots $

[Phys. Rev. B 95, 155138] Published Mon Apr 24, 2017

]]>Lattice thermal conductivity is one of the most important thermoelectric parameters in determining the energy conversion efficiency of thermoelectric materials. However, the lattice thermal conductivity evaluation requires time-consuming first-principles (quasi)phonon calculations, which limits seek…

[Phys. Rev. B 95, 155206] Published Mon Apr 24, 2017

]]>Surface magnetism is analyzed by spin-dependent ${\mathrm{He}}^{+}$-ion neutralization (the Auger neutralization) in the vicinity of a surface using an electron spin-polarized low-energy ${\mathrm{He}}^{+}$-ion beam [spin-polarized ion scattering spectroscopy (SP-ISS)]. Recently, spin-orbit coupling (SOC) has been found to act as …

[Phys. Rev. B 95, 155437] Published Mon Apr 24, 2017

]]>We present an analytical tight-binding theory of the optical properties of graphene nanoribbons with zigzag edges. Applying the transfer matrix technique to the nearest-neighbor tight-binding Hamiltonian, we derive analytical expressions for electron wave functions and optical transition matrix elem…

[Phys. Rev. B 95, 155438] Published Mon Apr 24, 2017

]]>The recent experiment of Stettenheim et al. showed that, contrary to conventional belief, the coupling of a quantum electronic device to its substrate can have important effects on the noise power spectrum, since the substrate functions as a mechanical oscillator. We carry out a theoretical analysi…

[Phys. Rev. B 95, 155439] Published Mon Apr 24, 2017

]]>Commensurate magnetoresistance periodic oscillations generated by transversal electron snake orbits are found experimentally. A two-dimensional electron gas is exposed to a magnetic field that changes sign along the current longitudinal direction and is homogeneous in the transverse direction. The c…

[Phys. Rev. B 95, 155440] Published Mon Apr 24, 2017

]]>Extrinsic optical chirality in a form of the asymmetric transmission of circularly polarized light at the oblique light incidence has been observed in three-dimensional opal photonic crystals assembled from monodisperse polymer spheres in the closely packed face-centered-cubic lattice. This effect h…

[Phys. Rev. B 95, 155441] Published Mon Apr 24, 2017

]]>This paper reports on the observation of the magnetic quantum ratchet effect in (Cd,Mn)Te- and CdTe-based quantum well structures with an asymmetric lateral dual grating gate superlattice subjected to an external magnetic field ($B$), applied normal to the quantum well plane. An electric current excited by terahertz laser radiation shows 1/$B$-periodic oscillations with amplitude much larger than the photocurrent at zero magnetic field. It is shown that the photocurrent generation is due to the combined action of a spatially periodic lateral potential and the spatially modulated radiation due to the near-field effects of light diffraction. The magnitude and direction of the photocurrent are determined by the degree of the lateral asymmetry controlled by the variation of voltages applied to the individual gates. The observed magneto-oscillations with enhanced photocurrent amplitude result from Landau quantization. For (Cd,Mn)Te-based structures at low temperatures, a beating-like pattern of the oscillations is observed, caused by the interplay of Zeeman and Landau splitting. A theoretical analysis, considering the magnetic quantum ratchet effect in the framework of a semiclassical approach, describes quite well the experimental results.

[Phys. Rev. B 95, 155442] Published Mon Apr 24, 2017

]]>[Phys. Rev. B 95, 159907] Published Mon Apr 24, 2017

]]>Multi-Weyl semimetals are new types of Weyl semimetals which have anisotropic nonlinear energy dispersion and a topological charge larger than one, thus exhibiting a unique quantum response. Using a unified lattice model, we calculate the optical conductivity numerically in the multi-Weyl semimetal …

[Phys. Rev. B 95, 161112(R)] Published Mon Apr 24, 2017

]]>Multi-Weyl semimetals (m-WSMs) are a new type of Weyl semimetal that have linear dispersion along one symmetry direction but anisotropic nonlinear dispersion along the two transverse directions with a topological charge larger than one. Using the Boltzmann transport theory and fully incorporating th…

[Phys. Rev. B 95, 161113(R)] Published Mon Apr 24, 2017

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