Incandescent sources that produce light from electrically heated filaments or films tend to feature low efficiencies and offer poor spectral and angular control. We demonstrate that a judicious nanostructuring of a SiC surface can focus thermal emission of a preselected spectral range to a well-defi…

[Phys. Rev. B 94, 094307] Published Fri Sep 23, 2016

]]>The decohering environment of a quantum bit is often described by the coupling to a large bath of spins. The quantum bit itself can be seen as a spin $S=\frac{1}{2}$ which is commonly called the central spin. The resulting central spin model describes an important mechanism of decoherence. We provide mathemati…

[Phys. Rev. B 94, 094308] Published Fri Sep 23, 2016

]]>In order to elucidate the origin of the temperature ($T$) dependence of spin-dependent tunneling conductance ($G$) of magnetic tunnel junctions (MTJs), we experimentally investigated the $T$ dependence of $G$ for the parallel and antiparallel magnetization alignments, ${G}_{\mathrm{P}}$ and ${G}_{\mathrm{AP}}$, of high-quality $\mathrm{C}{\mathrm{o}}_{2}\mathrm{MnSi}$ (CM…

[Phys. Rev. B 94, 094428] Published Fri Sep 23, 2016

]]>We use scanning electron microscopy with polarization analysis to image deterministic, spin-orbit torque-driven magnetization reversal of in-plane magnetized CoFeB rectangles in zero applied magnetic field. The spin-orbit torque is generated by running a current through heavy metal microstrips, eith…

[Phys. Rev. B 94, 094429] Published Fri Sep 23, 2016

]]>The site-diluted compound ${\left({\mathrm{Yb}}_{1-x}{\mathrm{Lu}}_{x}\right)}_{4}{\mathrm{As}}_{3}$ is a scarce realization of the linear Heisenberg antiferromagnet partitioned into finite-size segments and is an ideal model compound for studying field-dependent effects of quenched disorder in the one-dimensional antiferromagnets. It differentiates from the…

[Phys. Rev. B 94, 100403(R)] Published Fri Sep 23, 2016

]]>The magnetoresistance and magnetic torque of FeS are measured in magnetic fields $B$ of up to 18 T down to a temperature of 0.03 K. The superconducting transition temperature is found to be ${T}_{c}=4.1\phantom{\rule{0.28em}{0ex}}\mathrm{K}$, and the anisotropy ratio of the upper critical field ${B}_{c2}$ at ${T}_{c}$ is estimated from the initial slopes to …

[Phys. Rev. B 94, 100503(R)] Published Fri Sep 23, 2016

]]>The high-pressure structural and elastic properties of ${\mathrm{MgCO}}_{3},{\mathrm{CaCO}}_{3}$, and $\mathrm{MgCa}{\left({\mathrm{CO}}_{3}\right)}_{2}$ have been investigated with density functional theory. By computing the isotropic elastic constants, we found that the bulk and shear acoustic wave velocities are smaller in carbonates than in their respective silica…

[Phys. Rev. B 94, 104112] Published Fri Sep 23, 2016

]]>Electronic, structural, and magnetic properties of Pt dichalcogenide monolayers are investigated using first-principle calculations. We find that hydrogenation lifts the spin degeneracy in narrow antibonding Pt $5d$ subband electrons and transforms the nonmagnetic semiconductors $\mathrm{Pt}{X}_{2}\phantom{\rule{0.16em}{0ex}}(X=\mathrm{S},\mathrm{Se},\mathrm{Te})$ into f…

[Phys. Rev. B 94, 104426] Published Fri Sep 23, 2016

]]>We present a comparative study of pair correlations and currents through superconducting-magnetic hybrid systems with a particular emphasis on the tunable Bloch domain wall of an exchange spring. This study of the Gor'kov functions contrasts magnetic systems with domain walls that change at discrete…

[Phys. Rev. B 94, 104518] Published Fri Sep 23, 2016

]]>Regular arrays of magnetic atoms on a superconductor provide a promising platform for topological superconductivity. In this work, we study the effects of disorder in these systems, focusing on vacancies realized by missing magnetic atoms. We develop approaches that allow treatment of ferromagnetic …

[Phys. Rev. B 94, 104519] Published Fri Sep 23, 2016

]]>Classification of possible quantum spin liquid (QSL) states of interacting spin-1/2's in two dimensions has been a fascinating topic of condensed matter for decades, resulting in enormous progress in our understanding of low-dimensional quantum matter. By contrast, relatively little work exists on t…

[Phys. Rev. B 94, 115150] Published Fri Sep 23, 2016

]]>In the prototypical $4d$ system $(\mathrm{Sr},\mathrm{Ca}){\mathrm{RuO}}_{3}$, the degree and origin of electron correlations, and how they correlate with physical properties, still remain elusive, though extensive studies have been performed. In this work we present a comparative electronic structure study of high-quality epitaxial ${\mathrm{C\dots}}_{}$

[Phys. Rev. B 94, 115151] Published Fri Sep 23, 2016

]]>Molecular adsorbates on metal surfaces exchange energy with substrate phonons and low-lying electron-hole pair excitations. In the limit of weak coupling, electron-hole pair excitations can be seen as exerting frictional forces on adsorbates that enhance energy transfer and facilitate vibrational re…

[Phys. Rev. B 94, 115432] Published Fri Sep 23, 2016

]]>A quantum critical (QC) fluid exhibits universal subleading corrections to the area law of its entanglement entropies. In two dimensions, when the partition involves a corner of angle $\theta $, the subleading term is logarithmic with coefficient ${a}_{\alpha}\left(\theta \right)$ for the $\alpha $-Rényi entropy. In the smooth limit $\theta \to \pi ,{a}_{1}\left(\theta \right)$ …

[Phys. Rev. B 94, 125142] Published Fri Sep 23, 2016

]]>Spin-polarized current through helimagnets and the conductance modulation due to the chirality mismatch are studied numerically. The one-dimensional spiral magnet structure is obtained by taking into account the Dzyaloshinskii-Moriya interaction and the ferromagnetic interaction. Although the spiral…

[Phys. Rev. B 94, 125143] Published Fri Sep 23, 2016

]]>The $\alpha -{T}_{3}$ model interpolates between the pseudospin $S=1/2$ honeycomb lattice of graphene and the pseudospin $S=1$ dice lattice via parameter $\alpha $. We present calculations of the magnetic properties of this hybrid pseudospin model, namely the absorptive magneto-optical conductivity and the Hofstadter butter…

[Phys. Rev. B 94, 125435] Published Fri Sep 23, 2016

]]>Neutron diffraction, Mössbauer spectroscopy, magnetometry, and in-field x-ray diffraction are employed to investigate the magnetoelastic phase transition in hexagonal ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_{2}\left(\mathrm{P},\mathrm{Si}\right)$ compounds. ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_{2}\left(\mathrm{P},\mathrm{Si}\right)$ compounds undergo for certain compositions a second-order paramagnetic (PM) to a spin-densit…

[Phys. Rev. B 94, 094426] Published Thu Sep 22, 2016

]]>We report results of joint experimental and theoretical studies on magnetoelectric (ME) compounds ${\mathrm{Co}}_{4}{\mathrm{Nb}}_{2}{\mathrm{O}}_{9}$ and ${\mathrm{Co}}_{4}{\mathrm{Ta}}_{2}{\mathrm{O}}_{9}$. On the experimental side, we present results of the magnetization and dielectric permittivity measurements in the magnetic field. On the theoretical side, we construct the low-ene…

[Phys. Rev. B 94, 094427] Published Thu Sep 22, 2016

]]>We show that Berezinskii's classification of the symmetries of Cooper pair amplitudes holds for driven systems even in the absence of translation invariance. We then consider a model Hamiltonian for a superconductor coupled to an external driving potential and, treating the drive as a perturbation, …

[Phys. Rev. B 94, 094518] Published Thu Sep 22, 2016

]]>We demonstrate amplification (and attenuation) of a probe signal by a driven two-level quantum system in the Landau-Zener-Stückelberg-Majorana regime by means of an experiment, in which a superconducting qubit was strongly coupled to a microwave cavity, in a conventional arrangement of circuit quant…

[Phys. Rev. B 94, 094519] Published Thu Sep 22, 2016

]]>A longstanding controversy for relaxor ferroelectrics has been the origin of the “waterfall” effect in the phonon dispersion curves, in which low-energy transverse phonons cascade into vertical columns. Originally interpreted as phonons interacting with polar nanoregions (PNRs), it was later explain…

[Phys. Rev. B 94, 104304] Published Thu Sep 22, 2016

]]>${\mathrm{Co}}_{2}\mathrm{FeAl}$ (CFA) thin films, of various thicknesses ($3\phantom{\rule{0.28em}{0ex}}\text{nm}\le t\le 50\phantom{\rule{0.28em}{0ex}}\mathrm{nm}$), have been grown by sputtering on (001) MgO single-crystal substrates and annealed at different temperatures ($\text{RT}\le {T}_{a}\le 600\phantom{\rule{0.16em}{0ex}}{}^{\circ}\mathrm{C}$, where RT is the room temperature). The influence of the CFA thickness ($t$), as well as *ex situ* annealing temperature…

[Phys. Rev. B 94, 104424] Published Thu Sep 22, 2016

]]>Exchange bias and coercivity are both studied numerically in antiferromagnetic/ferromagnetic (AFM/FM) bilayers in the presence of a rough interface. The roughness is modeled by an AFM atomic mesa of variable width, in a periodic bidimensional system. Unlike the flat interface case, roughness can fav…

[Phys. Rev. B 94, 104425] Published Thu Sep 22, 2016

]]>We utilize a combination of an *ab initio* calculation of effective Coulomb interactions and a DFT+DMFT calculation of total energy to study the structural properties of pure actinides. We first show that the effective direct Coulomb interactions in plutonium and americium are much smaller than usuall…

[Phys. Rev. B 94, 115148] Published Thu Sep 22, 2016

]]>We present a simple technique to calculate spin-orbit coupling, $\langle \mathbf{L}\xb7\mathbf{S}\rangle $, and branching ratio measured in x-ray absorption spectroscopy. Our method is for first-principles electronic structure calculation, and its implementation is straightforward for any of the standard formulations and codes. We appl…

[Phys. Rev. B 94, 115149] Published Thu Sep 22, 2016

]]>The gap equations for the surface quasiparticle propagators in a slab of three-dimensional topological insulator in external electric and magnetic fields perpendicular to the slab surfaces are analyzed and solved. A different type of magnetic catalysis is revealed with the dynamical generation of *bo…*

[Phys. Rev. B 94, 115429] Published Thu Sep 22, 2016

]]>Majorana bound states (MBS) differ from the regular zero energy Andreev bound states in their nonlocal properties, since two MBS form a single fermion. We design strategies for detection of this nonlocality by using the phenomenon of Coulomb-mediated Majorana coupling in a setting which still retain…

[Phys. Rev. B 94, 115430] Published Thu Sep 22, 2016

]]>In the two-dimensional electron gas emerging at the transition metal oxide surface and interface, various exotic electronic ordering and topological phases can become experimentally more accessible with the stronger Rashba spin-orbit interaction. Here, we present a promising route to realize signifi…

[Phys. Rev. B 94, 115431] Published Thu Sep 22, 2016

]]>Among a variety of layered materials used as building blocks in van der Waals heterostructures, hexagonal boron nitride (hBN) appears as an ideal platform for hosting optically active defects owing to its large band gap ($\sim 6\mathrm{eV}$). Here we study the optical response of a high-purity hBN crystal under g…

[Phys. Rev. B 94, 121405(R)] Published Thu Sep 22, 2016

]]>We present an experimental investigation on the universality of the optical transmittance of mono- and multilayer chemically exfoliated graphene flakes. By varying the exfoliating solvent, and thereby modulating the strength of electron-electron interactions, we find that the universality is not imp…

[Phys. Rev. B 94, 121406(R)] Published Thu Sep 22, 2016

]]>Materials with strong spin-orbit coupling often host a unique electronic structure, both in the bulk and on the surface. In particular, in systems that break inversion symmetry, spin-orbit coupling facilitates the Rashba-Dresselhaus effect, leading to a lifting of spin degeneracy in the bulk and intricate spin textures of the Bloch wave functions. Such materials could see potential applications in spintronics and quantum information technology, but these applications would benefit from a broader suite of materials, with a greater range of properties, and in particularly from very strong spin-orbit splitting. This paper’s angular-resolved photoemission and low-temperature scanning tunneling microscopy experiments, together with relativistic first-principles band structure calculations, identify several Dirac surface states in BiPd, one of which exhibits an extremely large spin splitting. Unlike the surface states in inversion-symmetric systems, the Dirac surface states of BiPd have completely different properties at opposite faces of the crystal and are not trivially linked by symmetry. The spin splitting of the surface states exhibits a strong anisotropy by itself, which can be linked to the low in-plane symmetry of the surface termination. Both may be useful to implement new functionalities for spintronic applications.

[Phys. Rev. B 94, 121407(R)] Published Thu Sep 22, 2016

]]>Berry curvature hot spots in two-dimensional materials with broken inversion symmetry are responsible for the existence of transverse valley currents, which give rise to giant nonlocal dc voltages. Recent experiments in high-quality gapped graphene have highlighted a saturation of the nonlocal resis…

[Phys. Rev. B 94, 121408(R)] Published Thu Sep 22, 2016

]]>The electrical resistivity and Hall effect of alkaline-earth-metal hexaboride single crystals are measured as a function of temperature, hydrostatic pressure, and magnetic field. The transport properties vary weakly with the external parameters and are modeled in terms of intrinsic variable-valence …

[Phys. Rev. B 94, 125141] Published Thu Sep 22, 2016

]]>In the present work, the problem of an all-coupling analytic description for the optical conductivity of the Fröhlich polaron is treated, with the goal being to bridge the gap in the validity range that exists between two complementary methods: on the one hand, the memory-function formalism and, on …

[Phys. Rev. B 94, 125206] Published Thu Sep 22, 2016

]]>The modulation by a surface acoustic wave (SAW) provides a powerful tool for the formation of tunable lattices of exciton-polariton macroscopic quantum states (MQSs) in semiconductor microcavities. The MQSs were resonantly excited in an optical parametric oscillator configuration. We investigate the…

[Phys. Rev. B 94, 125432] Published Thu Sep 22, 2016

]]>We study full counting statistics of electron tunneling in Coulomb-blockade systems in the limit of short measuring-time intervals. This limit is particularly suited to identify correlations among tunneling events, but only when analyzing the charge-transfer statistics in terms of factorial cumulant…

[Phys. Rev. B 94, 125433] Published Thu Sep 22, 2016

]]>For systems of lattice anyons such as Majoranas and parafermions, the unconventional quantum statistics determines a set of global symmetries (e.g., fermion parity for Majoranas) admitting no relevant perturbations. Any operator that breaks these symmetries explicitly would violate locality if added…

[Phys. Rev. B 94, 125434] Published Thu Sep 22, 2016

]]>We analyze the temperature dependence of conductivity in thick granular ferromagnetic compounds $\mathrm{NiSi}{\mathrm{O}}_{2}$ and in thin weakly coupled films of Fe, Ni, and Py in the vicinity of the metal-to-insulator transition. Development of a resistivity minimum followed by a logarithmic variation of conductivity at …

[Phys. Rev. B 94, 094202] Published Wed Sep 21, 2016

]]>Using large-scale molecular-dynamics simulations for a system of ${10}^{6}$ particles, the response of a dense amorphous solid to the continuous expansion of its volume is investigated. We find that the spatially uniform glassy state becomes unstable via the formation of cavities, which eventually leads to…

[Phys. Rev. B 94, 094203] Published Wed Sep 21, 2016

]]>Aggregates of magnetic nanoparticles (MNPs) exhibit unusual properties due to the interplay of small system size and long-range dipole-dipole interactions. Using the micromagnetic simulation software oommf, we study the spin morphologies and heat dissipation in micron-size spherical assemblies of MN…

[Phys. Rev. B 94, 094425] Published Wed Sep 21, 2016

]]>We study the spin resonance in the superconducting state of iron-based materials within multiband models with two unequal gaps, ${\mathrm{\Delta}}_{L}$ and ${\mathrm{\Delta}}_{S}$, on different Fermi-surface pockets. We show that, due to the indirect nature of the gap entering the spin susceptibility at the nesting wave vector $\mathbf{Q}$, the total …

[Phys. Rev. B 94, 094517] Published Wed Sep 21, 2016

]]>We study the effect of electronic Coulomb correlations on the vacancy formation energy in paramagnetic $\alpha \text{\u2212}\mathrm{Fe}$ within *ab initio* dynamical mean-field theory. The calculated value for the formation energy is substantially lower than in standard density-functional calculations and in excellent agreement w…

[Phys. Rev. B 94, 100102(R)] Published Wed Sep 21, 2016

]]>The short-range ordered but long-range disordered structure of metallic glasses yields strong structural and dynamic heterogeneities. Stress relaxation is a technique to trace the evolution of stress in response to a fixed strain, which reflects the dynamic features phenomenologically described by t…

[Phys. Rev. B 94, 104203] Published Wed Sep 21, 2016

]]>TiN is an important material used as a diffusion barrier in microelectronic devices to prevent copper from contacting silicon. There is, however, little known about the elementary atomistic processes underlying the excellent performance of TiN. In this work, we perform a density functional theory st…

[Phys. Rev. B 94, 104303] Published Wed Sep 21, 2016

]]>Although NaFe(WO${}_{4}$)${}_{2}$ is not multiferroic itself, the magnetic order in this $S$=5/2 chain material is a reference for many multiferroic materials, such as MnWO${}_{4}$ and $R$MnO${}_{3}$, because NaFe(WO${}_{4}$)${}_{2}$ exhibits a transition from an incommensurate spiral order to a commensurate up-up-down-down structure. Here, the authors perform a very extensive study of the magnetic properties in the this double tungstate compound at low temperatures and high magnetic fields. A complex $B$-$T$ phase diagram is unveiled. Strong magnetoelastic anomalies with a relative contraction of the $b$ lattice parameter of up to 2.6 $\times $ 10${}^{-4}$ are associated with the up-up-down-down ordering, which appears in the commensurate and also in the anharmonic incommensurate structure. In contrast, the transition to the magnetically ordered phase, with a purely harmonic incommensurate spiral modulation, does not cause resolvable anomalies in the thermal expansion. Thus, the strong magnetoelastic anomaly coupling can be attributed to the lifting of magnetic frustration in the up-up-down-down structure, where neighboring moments align either parallel or antiparallel, although all these bonds are equivalent in the paramagnetic state.

[Phys. Rev. B 94, 104423] Published Wed Sep 21, 2016

]]>A Luttinger liquid coupled to a quantum impurity describes a large number of physical systems. The Hamiltonian consists of left- and right-moving fermions interacting among themselves via a density-density coupling and scattering off a localized transmitting and reflecting impurity. We solve exactly…

[Phys. Rev. B 94, 115142] Published Wed Sep 21, 2016

]]>The martensitic transformation in ${\mathrm{Ni}}_{2}{\mathrm{Mn}}_{1+x}{\mathrm{Sn}}_{1-x}$ alloys has been investigated within *ab initio* density functional theory. The experimental trend of a martensitic transition happening beyond $x=0.36$ is captured within these calculations. The microscopic considerations leading to this are traced to incr…

[Phys. Rev. B 94, 115143] Published Wed Sep 21, 2016

]]>The strongly constrained and appropriately normed (SCAN) semilocal density functional [J. Sun, A. Ruzsinszky, and J. P. Perdew, Phys. Rev. Lett. **115**, 036402 (2015)] obeys all 17 known exact constraints for meta-generalized-gradient approximations (meta-GGAs), and it includes some medium-range correl…

[Phys. Rev. B 94, 115144] Published Wed Sep 21, 2016

]]>We consider the fate of a helical edge state of a spin Hall insulator and its topological transition in presence of a circularly polarized light when coupled to various forms of environments. A Lindblad-type equation is developed to determine the fermion occupation of the Floquet bands. We find by u…

[Phys. Rev. B 94, 115145] Published Wed Sep 21, 2016

]]>Iron chalcogenide superconductors are multiorbital materials with strong electron correlations. Here we use angle-resolved photoemission spectroscopy to study orbital dependent correlation effects in single-layer $\mathrm{FeSe}/\mathrm{Nb}:{\mathrm{BaTiO}}_{3}/{\mathrm{KTaO}}_{3}$, an iron chalcogenide superconductor with high interfacial superco…

[Phys. Rev. B 94, 115146] Published Wed Sep 21, 2016

]]>In the conventional theory of density wave ordering in metals, the onset of spin density wave (SDW) order coincides with the reconstruction of the Fermi surfaces into small “pockets.” We present models which display this transition, while also displaying an alternative route between these phases via…

[Phys. Rev. B 94, 115147] Published Wed Sep 21, 2016

]]>Our recently proposed theoretical formulation [presented in D. Novko *et al.*, Phys. Rev. B **93**, 125413 (2016)] is used to study optical absorption and transmission in molybdenum disulfide $\left({\mathrm{MoS}}_{2}\right)$ monolayer as a function of incident photon energy and angle. The investigation is not focused on explorati…

[Phys. Rev. B 94, 115428] Published Wed Sep 21, 2016

]]>The self-consistent $\mathrm{GW}\mathrm{\Gamma}$ method satisfies the Ward-Takahashi identity (i.e., the gauge invariance or the local charge continuity) for arbitrary energy ($\omega $) and momentum ($\mathit{q}$) transfers. Its self-consistent first-principles treatment of the vertex $\mathrm{\Gamma}={\mathrm{\Gamma}}_{v}$ or ${\mathrm{\Gamma}}_{W}$ is possible to first order in the bare ($v$) or …

[Phys. Rev. B 94, 121116(R)] Published Wed Sep 21, 2016

]]>In this paper, we investigate the edge Majorana modes in the simplest possible $p{}_{x}+i{p}_{y}$ superconductor defined on surfaces with different geometries, the annulus, the cylinder, the Möbius band, and a cone (by cone we mean a cone with the tip cut away so it is topologically equivalent to the annulus an…

[Phys. Rev. B 94, 125137] Published Wed Sep 21, 2016

]]>Using the perturbative scaling equations and the numerical renormalization group, we study the characteristic energy scales in the Kondo impurity problem as a function of the exchange coupling constant $J$ and the conduction-band electron density. We discuss the relation between the energy gain (impur…

[Phys. Rev. B 94, 125138] Published Wed Sep 21, 2016

]]>Extensive studies have demonstrated the promising capability of the organic-inorganic hybrid halide perovskite ${\mathrm{CH}}_{3}{\mathrm{NH}}_{3}{\mathrm{PbI}}_{3}$ in solar cells with a high power conversion efficiency exceeding 20%. However, the intrinsic as well as extrinsic instabilities of this material remain the major challenge to the…

[Phys. Rev. B 94, 125139] Published Wed Sep 21, 2016

]]>We present a theory of quantum oscillations in insulators that are particle-hole symmetric and nontopological but with arbitrary band dispersion, at both zero and nonzero temperature. At temperatures $T$ less than or comparable to the gap, the dependence of oscillations on $T$ is markedly different from…

[Phys. Rev. B 94, 125140] Published Wed Sep 21, 2016

]]>The magnetic and electronic properties of the magnetically doped topological insulator ${\mathrm{Bi}}_{2-x}{\mathrm{Mn}}_{x}{\mathrm{Te}}_{3}$ were studied using electron-spin resonance (ESR) and measurements of static magnetization and electrical transport. The investigated high-quality single crystals of ${\mathrm{Bi}}_{2-x}{\mathrm{Mn}}_{x}{\mathrm{Te}}_{3}$ show a ferromagnetic pha…

[Phys. Rev. B 94, 125205] Published Wed Sep 21, 2016

]]>We show by spatially and time-resolved photoluminescence that the application of an electric field transverse to the plane of an intrinsic GaAs (111) quantum well (QW) allows the transport of photogenerated electron spins polarized along the direction perpendicular to the QW plane over distances exc…

[Phys. Rev. B 94, 125311] Published Wed Sep 21, 2016

]]>We study coherent optics in topological insulator surface states with broken time-reversal symmetry and develop a theory for the dynamical Hall effect driven by an intense electromagnetic field. The influence of the optical Stark effect enters as a nonlinear dependence on the optical field in the re…

[Phys. Rev. B 94, 125430] Published Wed Sep 21, 2016

]]>Metamaterials possess artificial bulk and surface electromagnetic states. Tamed dispersion properties of surface waves allow one to achieve a controllable super-Planckian radiative heat transfer (RHT) process between two closely spaced objects. We numerically demonstrate enhanced RHT between two two…

[Phys. Rev. B 94, 125431] Published Wed Sep 21, 2016

]]>We synthesized single crystals of composition ${\mathrm{Ba}}_{2}{\mathrm{CuSi}}_{2}{\mathrm{O}}_{6}{\mathrm{Cl}}_{2}$ and investigated their quantum magnetic properties. The crystal structure is closely related to that of the quasi-two-dimensional (2D) dimerized magnet ${\mathrm{BaCuSi}}_{2}{\mathrm{O}}_{6}$ also known as Han purple. ${\mathrm{Ba}}_{2}{\mathrm{CuSi}}_{2}{\mathrm{O}}_{6}{\mathrm{Cl}}_{2}$ has a singlet ground state with an exc…

[Phys. Rev. B 94, 094421] Published Tue Sep 20, 2016

]]>Zeeman spectra, dichroic signals, and neutron Bragg diffraction patterns generated by copper ions in magnetically ordered copper metaborate $\left(\mathrm{Cu}{\mathrm{B}}_{2}{\mathrm{O}}_{4}\right)$ are investigated within a minimal model of Cu atomic states. A theory platform, common to understanding optical spectra and neutron diffraction pattern…

[Phys. Rev. B 94, 094422] Published Tue Sep 20, 2016

]]>Ferrites with (inverse) spinel structure display a large variety of electronic and magnetic properties, making some of them interesting for potential applications in spintronics. We investigate the thermally induced interdiffusion of ${\mathrm{Ni}}^{2+}$ ions out of NiO into ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ ultrathin films, resulting in off-…

[Phys. Rev. B 94, 094423] Published Tue Sep 20, 2016

]]>To investigate the impact of both the CoFe ferromagnetic layer thickness and the capping paramagnetic layer on the tunnel magnetoresistance (TMR), we performed first-principles simulations on epitaxial magnetic tunnel junctions contacted with either CoFe or Ta paramagnetic capping layers. We observe…

[Phys. Rev. B 94, 094424] Published Tue Sep 20, 2016

]]>An unusual form of superconductivity, called Ising superconductivity, has recently been uncovered in mono- and few-layered transition metal dichalcogenides. This 2D superconducting state is characterized by the so-called Ising spin-orbit coupling (SOC), which produces strong oppositely oriented effe…

[Phys. Rev. B 94, 094515] Published Tue Sep 20, 2016

]]>We develop a method to study the effect of the superconducting transition on the resonant inelastic x-ray scattering (RIXS) signal in superconductors with an order parameter with an arbitrary symmetry within a quasiparticle approach. As an example, we compare the direct RIXS signal below and above t…

[Phys. Rev. B 94, 094516] Published Tue Sep 20, 2016

]]>Multiple relaxation times detected in the ac magnetic susceptibility of several single-molecule magnets have been always assigned to extrinsic factors, such as nonequivalent magnetic centers or effects of intermolecular interactions in the crystal. By solving quantum relaxation equations, we prove t…

[Phys. Rev. B 94, 104422] Published Tue Sep 20, 2016

]]>Superconducting qubits are among the most promising elements for the implementation of the concept of quantum computing. Quasiparticles are an intrinsic sources of qubit decoherence, and are more generally detrimental to the operation of superconducting devices, e.g., Cooper pair pumps. Experiments reveal that quasiparticles fail to equilibrate and their density remains high even at low temperatures. Planting normal-metal traps on a superconducting device offers a way to reduce the quasiparticle density: once a quasiparticle tunnels into the normal metal and relaxes to subgap energy via inelastic processes, it cannot return to the superconductor. This paper presents a theoretical model for the time-resolved dynamics of quasiparticles injected into a qubit, and experiments with transmon qubits validating the model. The authors show that, contrary to expectations, the effective trapping rate depends on temperature, which is a consequence of the strong energy dependence of the quasiparticle density of states in the superconductor. At low temperatures, the relaxation process in the normal metal is the bottleneck limiting the effectiveness of traps. The authors also show that the trapping rate saturates for larger traps. At saturation, the rate is limited by the inverse of the time it takes for quasiparticles to diffuse across the device.

[Phys. Rev. B 94, 104516] Published Tue Sep 20, 2016

]]>We performed a comprehensive angle-resolved photoemission spectroscopy study of the electronic band structure of LaOFeAs single crystals. We found that samples cleaved at low temperature show an unstable and highly complicated band structure, whereas samples cleaved at high temperature exhibit a sta…

[Phys. Rev. B 94, 104517] Published Tue Sep 20, 2016

]]>We study terahertz photoconductivity of a rutile single crystal between 10 and 300 K under strong photoexcitation by femtosecond pulses at 266 nm. A marked dependence of the carrier mobility on the carrier density is observed leading to highly complex transport phenomena on a picosecond time scale. …

[Phys. Rev. B 94, 115206] Published Tue Sep 20, 2016

]]>We find an unambiguous relationship between disorder-driven features in the temperature dependence of the resistance and the behavior, as functions of the temperature, of the parameters necessary to describe some of the relaxation processes in the photoinduced differential time-resolved reflectivity…

[Phys. Rev. B 94, 115426] Published Tue Sep 20, 2016

]]>The past few years have witnessed a rapid evolution of hybrid organic-inorganic perovskite solar cells as an unprecedented photovoltaic technology with both relatively low cost and high-power conversion. The fascinating physical and chemical properties of perovskites are benefited from their unique …

[Phys. Rev. B 94, 115427] Published Tue Sep 20, 2016

]]>There is strong interest in discovering or designing wide-gap Chern insulators. Here we follow a Chern insulator to trivial Mott insulator transition versus interaction strength $U$ in a honeycomb-lattice Fe-based transition-metal oxide, discovering that a spin-orbit coupling energy scale $\xi =40$ meV can…

[Phys. Rev. B 94, 125134] Published Tue Sep 20, 2016

]]>The interplay of electronic band structures and electron-electron interactions is known to develop new phases in condensed matter. In this paper, we investigate the thermodynamic phases and corresponding electronic structures of a Weyl semimetal in a strong on-site Coulomb interaction limit. Based o…

[Phys. Rev. B 94, 125135] Published Tue Sep 20, 2016

]]>Materials with a perfect kagome lattice structure of magnetic ions are intensively sought after, because they may exhibit exotic ground states like a quantum spin liquid phase. Barlowite is a natural mineral that features perfect kagome layers of copper ions. However, in barlowite there are also cop…

[Phys. Rev. B 94, 125136] Published Tue Sep 20, 2016

]]>We study the temperature-dependent electrical and optical properties of hybrid charge transfer excitons (HCTEs) at a ZnO/4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) organic/inorganic semiconductor heterojunction (OI-HJ). The electroluminescence spectrum of the HCTE formed by recombination of injected…

[Phys. Rev. B 94, 125429] Published Tue Sep 20, 2016

]]>The formation of nonlinear Bloch states in open driven-dissipative systems of exciton-polaritons loaded into a weak-contrast 1D periodic lattice is studied numerically and analytically. The condensate is described within the framework of mean-field theory by the coupled equations for the order param…

[Phys. Rev. B 94, 094306] Published Mon Sep 19, 2016

]]>A magnetic skyrmionium is a nontopological soliton, which has a doughnut-like out-of-plane spin texture in thin films, and can be phenomenologically viewed as a coalition of two topological magnetic skyrmions with opposite topological numbers. Due to its zero topological number ($Q=0$) and doughnut-li…

[Phys. Rev. B 94, 094420] Published Mon Sep 19, 2016

]]>The flow-equation method was proposed by Wegner as a technique for studying interacting systems in one dimension. Here, we apply this method to a disordered one-dimensional model with power-law decaying hoppings. This model presents a transition as function of the decaying exponent $\alpha $. We derive the …

[Phys. Rev. B 94, 104202] Published Mon Sep 19, 2016

]]>The response of the crystal lattice to an electric shift current induced via the two-photon bulk-photovoltaic effect in a lithium niobate (${\mathrm{LiNbO}}_{\text{3}}$) crystal is directly mapped by femtosecond x-ray diffraction. Acoustic strain waves of large amplitude are generated by piezoelectric coupling to the curr…

[Phys. Rev. B 94, 104302] Published Mon Sep 19, 2016

]]>${\mathrm{CuCrO}}_{2}$ is a manifestation of a two-dimensional triangular antiferromagnet which exhibits an incommensurate noncollinear magnetic structure similar to a classical ${120}^{\circ}$ ordering. Using the inelastic neutron scattering technique, direct evidence of a magnon-phonon coupling in ${\mathrm{CuCrO}}_{2}$ is revealed via the…

[Phys. Rev. B 94, 104421] Published Mon Sep 19, 2016

]]>We report single-crystal x-ray-diffraction measurements on ${\mathrm{Na}}_{2}{\mathrm{Ti}}_{2}P{n}_{2}\mathrm{O}\phantom{\rule{0.28em}{0ex}}(Pn=\mathrm{As},\mathrm{Sb})$ which reveal a charge superstructure that appears below the density wave transitions previously observed in bulk data. From symmetry-constrained structure refinements we establish that the associated distortion mode can …

[Phys. Rev. B 94, 104515] Published Mon Sep 19, 2016

]]>We show by means of *ab initio* calculations and tight-binding modeling that an oxide system based on a honeycomb lattice can sustain topologically nontrivial states if a single orbital dominates the spectrum close to the Fermi level. In such a situation, the low-energy spectrum is described by two Di…

[Phys. Rev. B 94, 115141] Published Mon Sep 19, 2016

]]>The effects of nonequilibrium constraints and dephasing on the circulating currents in molecular junctions are analyzed. Circulating currents are manifestations of quantum effects and can be induced either by externally applied bias or an external magnetic field through the molecular system. In a sy…

[Phys. Rev. B 94, 115424] Published Mon Sep 19, 2016

]]>A theoretical study of the localization properties of nanowires of dopants in silicon (Si) fabricated by ionic implantation or scanning tunnel microscope lithography is presented for a model incorporating the currently unavoidable imprecision in individual donor positioning. Experiments have shown t…

[Phys. Rev. B 94, 115425] Published Mon Sep 19, 2016

]]>We report the discovery of a topological semimetal, ${\mathrm{TaSb}}_{2}$, which crystallizes in a base-centered monoclinic, centrosymmetric structure. The compound undergoes a metal-insulator-like transition under magnetic field and exhibits a clear resistivity plateau below ${T}_{c}=13$ K. The ultrahigh carrier mobility…

[Phys. Rev. B 94, 121115(R)] Published Mon Sep 19, 2016

]]>We present a strong-coupling approach to the theory of high-temperature superconductivity based on the observation of a quantum critical point in the plaquette within the $t,{t}^{\prime}$ Hubbard model. The crossing of ground-state energies in the $N=2\u20134$ sectors occurs for parameters close to the optimal doping.…

[Phys. Rev. B 94, 125133] Published Mon Sep 19, 2016

]]>We present a microscopic calculation of spatially indirect exciton states in semiconductor coupled quantum wells and polaritons formed from their coupling to the optical mode of a microcavity. We include the presence of electric and magnetic fields applied perpendicular to the quantum well plane. Ou…

[Phys. Rev. B 94, 125310] Published Mon Sep 19, 2016

]]>We study Majorana fermions in a two-dimensional topological superconductor placed in a transverse magnetic-field $B$. We consider a topological insulator/superconductor heterostructure and a two-dimensional $p$-wave superconductor. A single field-generated vortex creates two Majorana fermions, one of wh…

[Phys. Rev. B 94, 125428] Published Mon Sep 19, 2016

]]>Using density-functional theory we compute the formation energies of vacancies $\square $ in the framework of type I ${\mathrm{Ba}}_{8}{\mathrm{Zn}}_{x}{\mathrm{Ge}}_{46-x-y}{\square}_{y}$ clathrates as a function of Zn substitutions. While resolving the contradiction on the experimental reports on the relation between the concentration of Zn, $x$, and the number …

[Phys. Rev. B 94, 094305] Published Fri Sep 16, 2016

]]>${\mathrm{Ba}}_{2}{\mathrm{CoGe}}_{2}{\mathrm{O}}_{7}$ exhibits a collinear-antiferromagnetic structure with the easy axis along $\langle 100\rangle $ directions and an antiferroelectric order with the polarization axis along the [001] direction. By applying the electric field the magnetic moment rotates from $\langle 100\rangle $ to [110] directions and, simultaneously, th…

[Phys. Rev. B 94, 094418] Published Fri Sep 16, 2016

]]>We show spin-transfer-torque-driven vortex oscillations in current-perpendicular-to-plane giant magnetoresistance junctions using epitaxially grown ${\mathrm{Co}}_{2}{\mathrm{Fe}}_{x}{\mathrm{Mn}}_{1-x}\mathrm{Si}$ (CFMS) Heusler alloy thin films. The soft magnetic property and high spin polarization of CFMS enable us to realize vortex oscillation emi…

[Phys. Rev. B 94, 094419] Published Fri Sep 16, 2016

]]>The critical current of a Josephson junction is an oscillatory function of the enclosed magnetic flux $\mathrm{\Phi}$, because of quantum interference modulated with periodicity $h/2e$. We calculate these Fraunhofer oscillations in a two-dimensional (2D) ballistic superconductor–normal-metal–superconductor (SNS) ju…

[Phys. Rev. B 94, 094514] Published Fri Sep 16, 2016

]]>Magnetocrystalline anisotropy at Heusler $\mathrm{alloy}|\mathrm{MgO}$ interfaces has been studied using first-principles calculations. It has been found that Co-terminated ${\mathrm{Co}}_{2}\mathrm{FeAl}|\mathrm{MgO}$ interfaces show perpendicular magnetic anisotropy up to 1.31 mJ/${\mathrm{m}}^{2}$, while those with FeAl termination exhibit in-plane magnetic anisotr…

[Phys. Rev. B 94, 104418] Published Fri Sep 16, 2016

]]>Spin transport at interfaces between nonmagnets and ferromagnets plays an important role in spintronic devices. Lately, there is an increasing suspicion that spin-orbit coupling, which couples the spin and momentum of carriers, might contribute significantly to this process. Unfortunately, the existing description of spin transport at such interfaces, magnetoelectronic circuit theory, is not valid when spin-orbit coupling is present at the interface. This paper presents a generalization of magnetoelectronic circuit theory to interfaces with spin-orbit coupling. Like the original theory, this generalization describes spin transport in terms of drops in spin and charge accumulations across the interface, but also includes responses to in-plane electric fields and offsets in spin accumulations. The most important result is a description of the way in-plane electric fields generate spin accumulations, spin currents, and torques at the interface. The effects described by this generalized circuit theory impact the interpretation of experiments involving spin-orbit torques, spin pumping, spin memory loss, the Rashba-Edelstein effect, and spin Hall magnetoresistance.

[Phys. Rev. B 94, 104419] Published Fri Sep 16, 2016

]]>Most spintronic devices share two features: they utilize spin-orbit coupling and they contain interfaces. While bulk spin-orbit effects are thought to be well described by phenomenological theories, interfacial spin-orbit effects are not. A theory that could describe interfacial spin-orbit effects would be useful in analyzing experiments on heavy-metal ferromagnet bilayers, which are a key feature of potential energy-efficient implementations of MRAM. To develop such a theory, the authors present the boundary conditions needed for drift-diffusion models to treat interfaces with spin-orbit coupling. Together with the drift-diffusion equations, these boundary conditions give an analytical model of spin-orbit torques caused by both the spin Hall and Rashba-Edelstein effects. A key feature of these boundary conditions is that they capture spin currents generated by interfacial spin-orbit scattering. The authors validate this phenomenological approach by comparing the results with those obtained by solving the spin-dependent Boltzmann equation. They discuss the interpretation of current experiments, and describe in particular how interfacial effects give rise to torques on a nearby ferromagnetic layer even through a nonmagnetic spacer layer.

[Phys. Rev. B 94, 104420] Published Fri Sep 16, 2016

]]>Superconducting thin films of the noncentrosymmetric superconductor ${\mathrm{Nb}}_{0.18}{\mathrm{Re}}_{0.82}$ were successfully deposited by UHV sputtering technique. X-ray diffraction analysis indicated that the films are polycrystalline, with a preferential ($nn0$) orientation and the lattice parameter in agreement with the ex…

[Phys. Rev. B 94, 104512] Published Fri Sep 16, 2016

]]>Motivated by the recent realization of the three-dimensional hyperhoneycomb and stripyhoneycomb lattices in lithium iridate (${\mathrm{Li}}_{2}{\mathrm{IrO}}_{3}$), we study the possible spin-singlet superconducting states on the whole series of harmonic honeycomb lattices. Beginning with an isolated out-of-plane twist making th…

[Phys. Rev. B 94, 104513] Published Fri Sep 16, 2016

]]>We study magnetotransport properties of the electron-doped superconductor ${\mathrm{Pr}}_{2-x}{\mathrm{Ce}}_{x}{\mathrm{CuO}}_{4\pm \delta}$ with $x=0.14$ in magnetic fields up to 92 T, and observe Shubnikov-de Haas magnetic quantum oscillations. The oscillations display a single frequency $F=255\pm 10$ T, indicating a small Fermi pocket that is $\sim 1\%$ of the …

[Phys. Rev. B 94, 104514] Published Fri Sep 16, 2016

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