As the grain size decreases to the nanometer range, the characteristics of the ferroelectric nanoceramic can be ultimately determined by the competition between two effects: the intrinsic effect that is associated with the local properties of the grain boundary and the extrinsic effect that arises f…

[Phys. Rev. B 95, 054121] Published Fri Feb 24, 2017

]]>We use the first-principles approach to clarify the thermodynamic stability as a function of pressure and temperature of three different $\alpha $-rhombohedral-boron-like boron subnitrides, with the compositions of ${\mathrm{B}}_{6}\mathrm{N},{\mathrm{B}}_{13}{\mathrm{N}}_{2}$, and ${\mathrm{B}}_{38}{\mathrm{N}}_{6}$, proposed in the literature. We find that, out of these subnitrides wit…

[Phys. Rev. B 95, 064206] Published Fri Feb 24, 2017

]]>We report the first observation of Rabi oscillations in the spin-7/2 ensemble of trivalent gadolinium ions hosted in $\mathrm{CaW}{\mathrm{O}}_{4}$ single crystal. A number of transitions within the lowest electronic multiplet ${}^{8}{S}_{7/\phantom{72}\phantom{\rule{0.0pt}{0ex}}2}$ of $\mathrm{G}{\mathrm{d}}^{3+}$ ion are studied using a combination of continuous-wave and pulsed electron paramag…

[Phys. Rev. B 95, 064427] Published Fri Feb 24, 2017

]]>With the help of the exact solution of the Kitaev model the parametric pumping of the two-dimensional quantum spin liquid under the action of the ac magnetic field is studied. In the dynamical regime the field produces oscillations of the magnetization with the field's frequency, modulated by the Ra…

[Phys. Rev. B 95, 064428] Published Fri Feb 24, 2017

]]>Monolayer transition metal dichalcogenides (TMDCs) offer a tantalizing platform for control of both spin and valley degrees of freedom, which may enable future optoelectronic devices with enhanced and novel functionalities. Here, we investigate the valley dynamics of two prototypical members of TMDC…

[Phys. Rev. B 95, 075428] Published Fri Feb 24, 2017

]]>By using Fourier-transform scanning tunneling spectroscopy we measure the interference patterns produced by the impurity scattering of confined Dirac quasiparticles in epitaxial graphene nanoflakes. Upon comparison of the experimental results with tight-binding calculations of realistic model flakes…

[Phys. Rev. B 95, 075429] Published Fri Feb 24, 2017

]]>First-principles studies of the electron-phonon coupling in graphene predict a high coupling strength for the $\sigma $ band with $\lambda $ values of up to 0.9. Near the top of the $\sigma $ band, $\lambda $ is found to be $\approx 0.7$. This value is consistent with the recently observed kinks in the $\sigma $ band dispersion by angle-resolved pho…

[Phys. Rev. B 95, 075430] Published Fri Feb 24, 2017

]]>We consider a one-dimensional spin-$\frac{1}{2}$ chain with Heisenberg interaction in a disordered parallel magnetic field. This system is known to exhibit the many-body localization (MBL) transition at critical strength of disorder. We analyze the response of the chain when additional perpendicular magnetic f…

[Phys. Rev. B 95, 085139] Published Fri Feb 24, 2017

]]>One-dimensional organo-metal halide perovskite ($\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Pb}{\mathrm{I}}_{3}$) nanorods whose diameter and length are dictated by the inner size of porous silicon nanotube templates have been grown, characterized, and compared to bulk perovskites in the form of microwires. We have observed a structural phase transitio…

[Phys. Rev. B 95, 085433] Published Fri Feb 24, 2017

]]>The author investigates in a nonperturbative way the effects of Rashba interaction and electromagnetic field on the edge states of a two-dimensional topological insulator. He shows that the electron dynamics is equivalent to a problem of massless Dirac fermions propagating with an inhomogeneous velocity, unveiling interesting consequences. The Rashba coupling always enhances the electron velocity and, despite the inelastic and time-reversal breaking processes induced by the electromagnetic field, no backscattering occurs without interaction. Furthermore, when the photoexcitation occurs far from the Rashba region, the latter effectively acts as a “superluminal gate”, boosting the photoexcited wavepacket outside the light-cone determined by the bare Fermi velocity ${v}_{F}$. In contrast, for an electric pulse overlapping the Rashba region, the emerging wave packets are squeezed in a manner that depends on the overlap area. The author also discusses the effects of electron-electron interaction, for both intraspin and interspin density-density coupling. The results suggest that Rashba interaction, often considered as an unwanted disorder effect, may be exploited to tailor the shape and the propagation time of photoexcited spin-polarized wave packets.

[Phys. Rev. B 95, 085434] Published Fri Feb 24, 2017

]]>The authors present a method for characterizing the hyperuniformity (the suppression of density fluctuations at long wavelengths) for quasicrystals (and other structures whose diffraction pattern includes a dense set of Bragg peaks) based on determining the behavior of the integrated spectral intensity $Z$($k$) for small wavenumber $k$. Surprisingly, we find that quasicrystals with peaks at the same wavenumbers $k$ can have different behavior for $Z$($k$) and, hence, qualitatively different degrees of hyperuniformity. This effect has never been explored in the laboratory. The figure shows a one-dimensional example: two “sidewalks” with different widths (pitched at an incommensurate angle) built on a lawn with a square crystal pattern of spots. The construction rule is that, every time the sidewalk crosses a spot, the sidewalk slab is cut and a new one begins. This rule guarantees both sidewalks are quasicrystalline. But the upper one (a Fibonacci sidewalk) has a different degree of hyperuniformity than the lower one.

[Phys. Rev. B 95, 054119] Published Thu Feb 23, 2017

]]>The role of hydrogen in the photoluminescence (PL) of ZnO was investigated using four different types of bulk ZnO single crystal, with varying concentrations of unintentional hydrogen donor and Group I acceptor impurities. Photoluminescence spectra were measured at 3 K, with emission energies determ…

[Phys. Rev. B 95, 054120] Published Thu Feb 23, 2017

]]>We study quantum quenches in the XXZ spin-$1/2$ Heisenberg chain from families of ferromagnetic and antiferromagnetic initial states. Using Bethe ansatz techniques, we compute short-range correlators in the complete generalized Gibbs ensemble (GGE), which takes into account all local and quasilocal co…

[Phys. Rev. B 95, 054308] Published Thu Feb 23, 2017

]]>We followed the evolution of the normal and superconducting properties of Al thin films after each session of various successive oxygen irradiations at ambient temperature. Such irradiated films, similar to the granular ones, exhibit enhanced superconductivity, Kondo behavior, and negative-curvature…

[Phys. Rev. B 95, 054515] Published Thu Feb 23, 2017

]]>[Phys. Rev. B 95, 059904] Published Thu Feb 23, 2017

]]>We investigate the scattering of an electron by phonons in a small structure between two one-dimensional tight-binding leads. This model mimics the quantum electron transport through atomic wires or molecular junctions coupled to metallic leads. The electron-phonon-coupled structure is represented b…

[Phys. Rev. B 95, 064309] Published Thu Feb 23, 2017

]]>Magnetization, neutron diffraction, and high-energy x-ray diffraction results for Sn-flux grown single-crystal samples of $\mathrm{Ca}{\left({\mathrm{Co}}_{1-x}{\mathrm{Fe}}_{x}\right)}_{y}{\mathrm{As}}_{2}$, $0\le x\le 1$, $1.86\le y\le 2$, are presented and reveal that A-type antiferromagnetic order, with ordered moments lying along the $c$ axis, persists for $x\lesssim 0.12\left(1\right)$. The antiferr…

[Phys. Rev. B 95, 064425] Published Thu Feb 23, 2017

]]>We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field e…

[Phys. Rev. B 95, 064426] Published Thu Feb 23, 2017

]]>Here we report the discovery of superconductivity in multiple phases of the compressed $\mathrm{GeS}{\mathrm{b}}_{2}\mathrm{T}{\mathrm{e}}_{4}$ (GST) phase change memory alloy, which has attracted considerable attention for the last decade due to its unusual physical properties with many potential applications. Superconductivity is observed throu…

[Phys. Rev. B 95, 064514] Published Thu Feb 23, 2017

]]>Nonlocality is one of the most striking signatures of the topological nature of Weyl semimetals. We propose to probe the nonlocality in these materials via a measurement of a magnetic-field-dependent Coulomb drag between two sheets of graphene which are separated by a three-dimensional slab of Weyl …

[Phys. Rev. B 95, 075141] Published Thu Feb 23, 2017

]]>We study magnetic, transport, and thermodynamic properties of the half-filled two-dimensional $\left(2D\right)$ Hubbard model with layered distributed repulsive interactions using unbiased finite temperature quantum Monte Carlo simulations. Antiferromagnetic long-ranged correlations at $T=0$ are confirmed by means…

[Phys. Rev. B 95, 075142] Published Thu Feb 23, 2017

]]>The time evolution of a quantum system after a sudden change of one of its parameters may show characteristic nonanalyticities, provided that this quench crosses a quantum phase transition. The authors investigate the relation between such dynamical quantum phase transitions and the universal properties of the corresponding quantum critical point.

[Phys. Rev. B 95, 075143] Published Thu Feb 23, 2017

]]>Iron oxide is a key compound to understand the state of the deep Earth. It has been believed that previously known oxides such as FeO and ${\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ will be dominant at the mantle conditions. However, the recent observation of ${\mathrm{FeO}}_{2}$ shed another light to the composition of the deep lower mantle (DLM), and…

[Phys. Rev. B 95, 075144] Published Thu Feb 23, 2017

]]>In this work, we study the effects of spin-orbit and Coulomb anisotropy on the electronic and magnetic properties of the Mott insulator ${\mathrm{Ca}}_{2}{\mathrm{RuO}}_{4}$. We use the local-density approximation + dynamical mean-field approach and spin-wave theory. We show that, contrary to a recent proposal, the Mott metal-in…

[Phys. Rev. B 95, 075145] Published Thu Feb 23, 2017

]]>The intense theoretical and experimental interest in topological insulators and semimetals has established band structure topology as a fundamental material property. Consequently, identifying band topologies has become an important, but often challenging, problem, with no exhaustive solution at the…

[Phys. Rev. B 95, 075146] Published Thu Feb 23, 2017

]]>Due to its wide band gap and availability as a single crystal, $\beta -\mathrm{G}{\mathrm{a}}_{2}{\mathrm{O}}_{3}$ has potential for applications in many areas of micro/optoelectronics and photovoltaics. Still, little is as yet known about its intrinsic defects, which may influence carrier concentrations and act as recombination centers. From…

[Phys. Rev. B 95, 075208] Published Thu Feb 23, 2017

]]>We create an interface of graphene with a metallic and magnetic support that leaves its electronic structure largely intact. This is achieved by exposing epitaxial graphene on ferromagnetic thin films of Co and Ni to vapor of the rare earth metal Eu at elevated temperatures, resulting in the interca…

[Phys. Rev. B 95, 075427] Published Thu Feb 23, 2017

]]>[Phys. Rev. B 95, 079905] Published Thu Feb 23, 2017

]]>We have studied the magnetoresistance of a quantum point contact fabricated on a high mobility two-dimensional electron gas (2DEG) exposed to microwave irradiation. The resistance reveals giant $B$-periodic oscillations with a relative amplitude $\mathrm{\Delta}R/R$ of up to $700\%$ resulting from the propagation and in…

[Phys. Rev. B 95, 081408(R)] Published Thu Feb 23, 2017

]]>We study the interplay of particle-hole symmetry and fermion-vortex duality in multicomponent half-filled Landau levels, such as quantum Hall gallium arsenide bilayers and graphene. For the $\nu =1/2+1/2$ bilayer, we show that particle-hole-symmetric interlayer Cooper pairing of composite fermions leads …

[Phys. Rev. B 95, 085135] Published Thu Feb 23, 2017

]]>The electronic structure, magnetic exchange interactions, and spin-driven ferroelectricity in skyrmion host ${\mathrm{GaV}}_{4}{\mathrm{S}}_{8}$ have been studied on the basis of first-principles calculations and symmetry analysis. We find the reconstruction of band structure with the increasing value of Hubbard parameter *U*. The…

[Phys. Rev. B 95, 085136] Published Thu Feb 23, 2017

]]>Twisted bilayer graphene (tBLG) represents a family of unique materials with optoelectronic properties tuned by the rotation angle between the two layers. The presented work shows an additional way of tweaking the electronic structure of tBLG by modifying the interlayer distance, for example by a sm…

[Phys. Rev. B 95, 085138] Published Thu Feb 23, 2017

]]>We investigate the temperature-dependent conductivity of epitaxial multilayer graphene using THz time-domain spectroscopy and find evidence that the Fermi level in quasineutral graphene layers is pinned at the Dirac point by midgap states. We demonstrate that the scattering mechanisms result from th…

[Phys. Rev. B 95, 085311] Published Thu Feb 23, 2017

]]>The spin-orbit interaction of holes in zinc-blende semiconductors is much stronger than that of electrons. This makes the hole systems very attractive for possible spintronics applications. In three dimensions (3D), the dynamics of holes is described by well-known Luttinger Hamiltonian. However, mos…

[Phys. Rev. B 95, 085431] Published Thu Feb 23, 2017

]]>An electromagnetic response of a single graphene layer to a uniform, arbitrarily strong electric field $\mathit{E}\left(t\right)$ is calculated by solving the kinetic Boltzmann equation within the relaxation-time approximation. The theory is valid at low (microwave, terahertz, infrared) frequencies satisfying the conditi…

[Phys. Rev. B 95, 085432] Published Thu Feb 23, 2017

]]>High-precision measurements of the specific volume and electrical resistivity of $\mathrm{A}{\mathrm{s}}_{2}\mathrm{T}{\mathrm{e}}_{3}$ glasses are performed under hydrostatic pressures up to 8.5 GPa. A smooth transformation and logarithmic relaxation of the density is observed at pressures higher than 1 GPa. The softening of the effective bulk m…

[Phys. Rev. B 95, 054205] Published Wed Feb 22, 2017

]]>The Hohenberg-Kohn theorem establishes a basis for mapping the exact energy functional to a model one provided that their charge densities coincide. We suggest to use a mapping in a similar spirit, but here the parameters of the formulated multiorbital model should minimize the difference between th…

[Phys. Rev. B 95, 054429] Published Wed Feb 22, 2017

]]>In superconductors with strong coupling between superconductivity and elasticity manifested in a strong dependence of transition temperature on pressure, there is an additional contribution to intervortex interactions due to the strain field generated by vortices. When vortex lines are along the $c$ a…

[Phys. Rev. B 95, 054511] Published Wed Feb 22, 2017

]]>Using muon spin rotation and infrared spectroscopy, we study the relation between magnetism and superconductivity in ${\mathrm{Ba}}_{1-x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ single crystals from the underdoped to the slightly overdoped regime. We find that the Fe magnetic moment is only moderately suppressed in most of the underdoped region …

[Phys. Rev. B 95, 054512] Published Wed Feb 22, 2017

]]>We show that under an ac magnetic field excitation the vortex lattice in a superconductor with a periodic array of holes can undergo a transition from a Mott-like state where each vortex is localized in a hole, to a metal-like state where the vortices get delocalized. The vortex dynamics is studied …

[Phys. Rev. B 95, 054513] Published Wed Feb 22, 2017

]]>We study Hanbury Brown and Twiss current cross-correlations in a three-terminal junction where a central topological superconductor (TS) nanowire, bearing Majorana bound states at its ends, is connected to two normal leads. Relying on a nonperturbative Green function formalism, our calculations allo…

[Phys. Rev. B 95, 054514] Published Wed Feb 22, 2017

]]>We report the measurement of the statistics of photons in the nonclassical radiation emitted by a tunnel junction. This is obtained by measuring up to the fourth cumulant of the voltage fluctuations generated by the sample. When the electron shot noise generates a squeezed electromagnetic field, the…

[Phys. Rev. B 95, 060301(R)] Published Wed Feb 22, 2017

]]>We study the quantum spin dynamics of nearly isotropic ${\mathrm{Gd}}^{3+}$ ions entrapped in polyoxometalate molecules and diluted in crystals of a diamagnetic ${\mathrm{Y}}^{3+}$ derivative. The full energy-level spectrum and the orientations of the magnetic anisotropy axes have been determined by means of continuous-wave electr…

[Phys. Rev. B 95, 064423] Published Wed Feb 22, 2017

]]>It has been argued that the itinerant magnetism in the simplest of all iron arsenide systems, the monoarsenide FeAs, may be related to the magnetic ground states of iron-based superconductors. Here, the authors provide new insight into the magnetism of FeAs through a combination of resonant x-ray scattering measurements and electronic structure calculations. They report measurements of the magnetic anisotropy of the spin helices by using polarized x-rays tuned to the resonant absorption edge of iron. They elucidate details of the magnetic structure, showing that the ratio of ellipticity of the spin helix is significantly larger than previously thought, and discover both a right-handed chirality and an out-of-plane component of the magnetic moments in the spin helix. The electronic structure calculations demonstrate how the origin of this spin canting effect may be accounted for by considering the spin-orbit coupling at work in the system.

[Phys. Rev. B 95, 064424] Published Wed Feb 22, 2017

]]>The two-dimensional Weyl superconductor is the most elusive member of a group of materials with Weyl fermions as low-energy excitations. Here, we propose to realize this state in a heterostructure consisting of thin films of half-metal and spin-singlet superconductors. In particular, for the $d$-wave …

[Phys. Rev. B 95, 064513] Published Wed Feb 22, 2017

]]>We investigate the ground state and finite-temperature properties of the spin-1/2 Heisenberg antiferromagnet on an infinite octa-kagome lattice by utilizing state-of-the-art tensor network-based numerical methods. It is shown that the ground state has a vanishing local magnetization and possesses a $\mathrm{\dots}$

[Phys. Rev. B 95, 075140] Published Wed Feb 22, 2017

]]>In this paper, we present evidence for the resonances between higher subbands in an asymmetric quadruple-quantum-well (AQQW) superlattice (SL) by photoluminescence (PL) spectra. Since each QW in an AQQW is separated by thin barriers, subband interferences can easily arise. As a result, various PL br…

[Phys. Rev. B 95, 075309] Published Wed Feb 22, 2017

]]>We consider a problem of persistent magnetization precession in a single-domain ferromagnetic nanoparticle under the driving by the spin-transfer torque. We find that the adjustment of the electronic distribution function in the particle renders this state unstable. Instead, abrupt switching of the …

[Phys. Rev. B 95, 075425] Published Wed Feb 22, 2017

]]>We study the unique physical properties of topological nodal-loop semimetals protected by the coexistence of time-reversal and inversion symmetries with negligible spin-orbit coupling. We argue that strong correlation effects occur at the surface of such systems for relatively small Hubbard interact…

[Phys. Rev. B 95, 075426] Published Wed Feb 22, 2017

]]>We use angle-resolved photoemission spectroscopy (ARPES) to explore the electronic structure of single crystals of FeSe over a wide range of binding energies and study the effects of strong electron-electron correlations. We provide evidence for the existence of “Hubbard-like bands” at high binding …

[Phys. Rev. B 95, 081106(R)] Published Wed Feb 22, 2017

]]>The electronic properties of single-layer antimony are studied by a combination of first-principles and tight-binding methods. The band structure obtained from relativistic density functional theory is used to derive an analytic tight-binding model that offers an efficient and accurate description o…

[Phys. Rev. B 95, 081407(R)] Published Wed Feb 22, 2017

]]>We present a computational method to quantitatively describe the linear-response conductance of nanoscale devices in the Kondo regime. This method relies on a projection scheme to extract an Anderson impurity model from the results of density functional theory and nonequilibrium Green's functions ca…

[Phys. Rev. B 95, 085131] Published Wed Feb 22, 2017

]]>Motivated by the experiments on the rare-earth double perovskites, we propose a generalized Kitaev-Heisenberg model to describe the generic interaction between the spin-orbit-entangled Kramers doublets of the rare-earth moments. We carry out a systematic analysis of the mean-field phase diagram of t…

[Phys. Rev. B 95, 085132] Published Wed Feb 22, 2017

]]>We have conducted hard x-ray photoelectron spectroscopy investigations of the electronic structure changes and electron correlation phenomena which take place upon the photoinduced reversible phase transition between β- and $\lambda \text{\u2212}T{\mathrm{i}}_{3}\mathrm{O}$. From valence band spectra of β- and $\lambda \text{\u2212}T{\mathrm{i}}_{3}{\mathrm{O}}_{5}$, we have identified the …

[Phys. Rev. B 95, 085133] Published Wed Feb 22, 2017

]]>The convergence of a cluster expansion for lithium transition-metal (TM) oxides is improved by explicit treatment of TM magnetic moments. The approach is applied to layered $\mathrm{LiC}{\mathrm{o}}_{y}\mathrm{N}{\mathrm{i}}_{1-y}{\mathrm{O}}_{2}$ (NC). The ground state and low-lying excited state structures are identified, and the distribution of TM ions and …

[Phys. Rev. B 95, 085134] Published Wed Feb 22, 2017

]]>Heat transfer across metal-semiconductor interfaces involves multiple fundamental transport mechanisms such as elastic and inelastic phonon scattering, and electron-phonon coupling within the metal and across the interface. The relative contributions of these different transport mechanisms to the in…

[Phys. Rev. B 95, 085310] Published Wed Feb 22, 2017

]]>Silicides are used extensively in nano- and microdevices due to their low electrical resistivity, low contact resistance to silicon, and their process compatibility. In this work, the thermal interface conductance of ${\mathrm{TiSi}}_{2},{\mathrm{CoSi}}_{2}$, NiSi, and PtSi are studied using time-domain thermoreflectance. Explo…

[Phys. Rev. B 95, 085430] Published Wed Feb 22, 2017

]]>Dielectric and mechanical spectroscopies have been used to investigate ferroelectric transitions and twin wall dynamics in the lead-free ceramic $0.5\mathrm{Ba}\left(\mathrm{Z}{\mathrm{r}}_{0.2}\mathrm{T}{\mathrm{i}}_{0.8}\right){\mathrm{O}}_{3}-0.5\left(\mathrm{B}{\mathrm{a}}_{0.7}\mathrm{C}{\mathrm{a}}_{0.3}\right)\mathrm{Ti}{\mathrm{O}}_{3}$ (abbreviated as BZT-50BCT), which is known to have a high piezoelectric coefficient (${d}_{33}>545\phantom{\rule{0.16em}{0ex}}\mathrm{pC}/\mathrm{N}$). Results from …

[Phys. Rev. B 95, 054116] Published Tue Feb 21, 2017

]]>Applying time-varying magnetic fields to Weyl metals, a pair of Weyl points becomes oscillating. This oscillating monopole and antimonopole pair gives rise to ac Berry magnetic fields, responsible for the emergence of Berry electric fields, which have not been discussed before at least in the contex…

[Phys. Rev. B 95, 054117] Published Tue Feb 21, 2017

]]>We investigate the high-pressure behavior of beryllium, magnesium, and calcium difluorides using *ab initio* random structure searching and density functional theory (DFT) calculations, over the pressure range $0\u201370$ GPa. Beryllium fluoride exhibits extensive polymorphism at low pressures, and we find t…

[Phys. Rev. B 95, 054118] Published Tue Feb 21, 2017

]]>We study the multipole interactions between ${f}^{2}$ ions with the ${\mathrm{\Gamma}}_{3}$ non-Kramers doublet ground state under a cubic crystalline electric field. We construct the ${\mathrm{\Gamma}}_{3}$ doublet state of the electrons with the total angular momentum $j=5/2$. By applying the second-order perturbation theory with respect to the in…

[Phys. Rev. B 95, 054425] Published Tue Feb 21, 2017

]]>Using an efficient first-principles computational scheme for paramagnetic body-centered cubic (bcc) and face-centered cubic (fcc) Fe, we investigate the impact of thermal longitudinal spin fluctuations (LSFs) on the thermal lattice expansion. The equilibrium physical parameters are derived from the …

[Phys. Rev. B 95, 054426] Published Tue Feb 21, 2017

]]>Transmittance spectra of $\mathrm{TbFe}{\mathrm{O}}_{3}$ single crystals have been studied in the far-infrared spectral range $15-120\phantom{\rule{0.16em}{0ex}}\mathrm{c}{\mathrm{m}}^{-1}$ in the external magnetic fields up to 9 T and at low temperatures down to 1.5 K. The temperature and magnetic-field dependencies of the antiferromagnetic resonance (AFMR) modes have been m…

[Phys. Rev. B 95, 054427] Published Tue Feb 21, 2017

]]>We study the effect of sputter-deposition conditions, namely, substrate temperature and chamber base pressure, upon the interface quality of epitaxial Pt/Co/Pt thin films with perpendicular magnetic anisotropy. Here we define interface quality to be the inverse of the sum in quadrature of roughness …

[Phys. Rev. B 95, 054428] Published Tue Feb 21, 2017

]]>Among hundreds of spinel oxides, $\mathrm{LiT}{\mathrm{i}}_{2}{\mathrm{O}}_{4}$ (LTO) is the only one that exhibits superconductivity (${T}_{\mathrm{c}}\sim 13\phantom{\rule{0.16em}{0ex}}\mathrm{K}$). Although the general electron-phonon coupling is still the main mechanism for electron pairing in LTO, unconventional behaviors such as the anomalous magnetoresistance, anisotropic orbital/spin s…

[Phys. Rev. B 95, 054510] Published Tue Feb 21, 2017

]]>[Phys. Rev. B 95, 059903] Published Tue Feb 21, 2017

]]>Understanding the spread of quantum entanglement and scrambling of information across a quantum many-body system is a fundamental problem in quantum dynamics. A necessary part of the spread of the entanglement is the growth in time of Heisenberg operators of initially localized operators. This operator growth can be diagnosed by studying the space-time structure of commutators of well-separated operators. Previous studies in this area focused on translation invariant models, but the effects of disorder, which can radically alter the motion of heat and charge, had not been studied. Here, the authors study the growth of operators in interacting systems with quenched disorder. In the localized phase, they find that operator sizes grow logarithmically in time similar to other measures of entanglement spreading. In the disordered metal, they find that operator sizes grow linearly with time, i.e., ballistically, in contrast to the diffusive motion of charge and heat. The ballistic growth of operators is quantified by the butterfly velocity which the authors relate to the charge diffusion constant and the interaction-induced inelastic scattering rate. When the diffusion of charge is slow, the resulting butterfly velocity is much smaller than the maximum speed allowed by microscopic causality constraints.

[Phys. Rev. B 95, 060201(R)] Published Tue Feb 21, 2017

]]>A trimer resonating valence bond (tRVB) state consisting of an equal-weight superposition of trimer coverings on a square lattice is proposed. A model Hamiltonian of the Rokhsar-Kivelson type for which the tRVB becomes the exact ground state is written. The state is shown to have ${9}^{g}$ topological dege…

[Phys. Rev. B 95, 060413(R)] Published Tue Feb 21, 2017

]]>To understand emergent magnetic monopole dynamics in the spin ices ${\mathrm{Ho}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ and ${\mathrm{Dy}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, it is necessary to investigate the mechanisms by which spins flip in these materials. Presently there are thought to be two processes: quantum tunneling at low and intermediate temperatures and thermally activa…

[Phys. Rev. B 95, 060414(R)] Published Tue Feb 21, 2017

]]>We report on the experimental verification of the rotational sense of homogeneous and antiferromagnetic spin spiral structures observed on mono- and double-layer Mn thin films formed on a W(110) substrate using spin-polarized scanning tunneling microscopy. By controlling the orientation of the tip m…

[Phys. Rev. B 95, 060415(R)] Published Tue Feb 21, 2017

]]>The structural and electronic response of $\mathrm{LaAl}{\mathrm{O}}_{3}$ to biaxial strain in the (111) plane is studied by density functional theory (DFT) and compared with strain in the (001) plane and isostatic strain. For (111) strain, in-plane rotations are stabilized by compressive strain and out-of-plane rotations b…

[Phys. Rev. B 95, 064109] Published Tue Feb 21, 2017

]]>The density matrix renormalization group (DMRG) is one of the most powerful numerical methods available for many-body systems. It has been applied to solve many physical problems, including the calculation of ground states and dynamical properties. In this work, we develop a perturbation theory of t…

[Phys. Rev. B 95, 064110] Published Tue Feb 21, 2017

]]>We present a theoretical approach to study nonequilibrium quantum heat transport in molecular junctions described by a spin-boson type model. Based on the Feynman-Vernon path integral influence functional formalism, expressions for the average value and high-order moments of the heat current operato…

[Phys. Rev. B 95, 064308] Published Tue Feb 21, 2017

]]>Magnetic domain wall (DW) motion induced by a localized Gaussian temperature profile is studied in a Permalloy nanostrip within the framework of the stochastic Landau-Lifshitz-Bloch equation. The different contributions to thermally induced DW motion, entropic torque and magnonic spin transfer torqu…

[Phys. Rev. B 95, 064419] Published Tue Feb 21, 2017

]]>We present a theory of the anisotropy of tunneling magnetoresistance (ATMR) phenomenon in magnetic tunnel junctions (MTJs) attributed to Rashba spin-orbit interaction in the insulating barrier. ATMR represents the difference of tunnel magnetoresistance (TMR) amplitude measured with in-plane and out-…

[Phys. Rev. B 95, 064420] Published Tue Feb 21, 2017

]]>Using pulsed magnetic fields up to $30\phantom{\rule{0.28em}{0ex}}\mathrm{T}$ we have measured the bulk magnetization and electrical polarization of ${\mathrm{LiNiPO}}_{4}$ and have studied its magnetic structure by time-of-flight neutron Laue diffraction. Our data establish the existence of a reentrant magnetoelectric phase between $19\phantom{\rule{0.28em}{0ex}}\mathrm{T}$ and $21\phantom{\rule{0.28em}{0ex}}\mathrm{T}$. We show…

[Phys. Rev. B 95, 064421] Published Tue Feb 21, 2017

]]>The foldover effect of nonlinear eigenmodes in feedback ring systems was observed. Experiments made use of a system that consisted of a magnetic thin film strip, which supported the propagation of spin waves, and a microwave amplifier, which amplified the signal from the output of the magnetic strip…

[Phys. Rev. B 95, 064422] Published Tue Feb 21, 2017

]]>A model of a clean two-band $s$-wave superconductor with cylindrical Fermi surfaces, different Fermi velocities ${v}_{1,2}$, and a general $2\times 2$ coupling matrix ${V}_{\alpha \beta}$ is used to study the order parameter distribution in vortex lattices. The Eilenberger weak coupling formalism is used to calculate numerically the…

[Phys. Rev. B 95, 064512] Published Tue Feb 21, 2017

]]>Topological Weyl semimetals (TWS) can be classified as type I TWS, in which the density of states vanishes at the Weyl nodes, and type II TWS, in which an electron pocket and a hole pocket meet at a singular point of momentum space, allowing for distinct topological properties. We consider various m…

[Phys. Rev. B 95, 075133] Published Tue Feb 21, 2017

]]>While ${\mathrm{SnS}}_{2}$ is an earth-abundant large-band-gap semiconductor material, the indirect nature of the band gap limits its applications in light harvesting or detection devices. Here, using density functional theory in combination with the many-body perturbation theory, we report indirect-to-direct band-…

[Phys. Rev. B 95, 075134] Published Tue Feb 21, 2017

]]>Recently, there have been extensive efforts to extend the physics of the two-dimensional (2D) graphene to three-dimensional (3D) semimetals with point/line nodes. Although it has been known that certain crystalline symmetries play an important role in protecting band degeneracy, a general recipe for stabilizing the degeneracy, especially in the presence of spin-orbit coupling, is still lacking. Here, the authors show that a class of novel topological semimetals with point/line nodes can emerge in the presence of an off-centered rotation/mirror symmetry whose symmetry line/plane is displaced from the center of other symmorphic symmetries in nonsymmorphic crystals. Due to the partial translation perpendicular to the rotation axis/mirror plane, an off-centered rotation/mirror symmetry always forces two energy bands to stick together and form a doublet pair in the relevant invariant line/plane in momentum space. Such a doublet pair provides a basic building block for emerging topological semimetals with point/line nodes in systems with strong spin-orbit coupling. When an external magnetic field is applied to these semimetals, a Dirac-type point/line node with four-fold degeneracy splits into two Weyl-type point/line nodes with two-fold degeneracy, with emergent surface states connecting the split nodes.

[Phys. Rev. B 95, 075135] Published Tue Feb 21, 2017

]]>We investigate the effect of introducing nearest-neighbor $p$-wave superconducting pairing to both the static and kicked extended Harper model with two periodic phase parameters acting as artificial dimensions to simulate three-dimensional systems. It is found that in both the static model and the kic…

[Phys. Rev. B 95, 075136] Published Tue Feb 21, 2017

]]>The Chern-Simons axion coupling of a bulk insulator is only defined modulo a quantum of ${e}^{2}/h$. The quantized part of the coupling is uniquely defined for a bounded insulating sample, but it depends on the specific surface termination. Working in a slab geometry and representing the valence bands in t…

[Phys. Rev. B 95, 075137] Published Tue Feb 21, 2017

]]>Topological semimetals are gapless states of matter which have robust surface states and characteristic electromagnetic responses. In this paper, we consider the electromagnetic response of gapless phases in $3+1$ dimensions with line nodes. We show through a layering approach that an intrinsic antisy…

[Phys. Rev. B 95, 075138] Published Tue Feb 21, 2017

]]>The magnetic correlations within the cuprates have undergone intense scrutiny as part of efforts to understand high-temperature superconductivity. We explore the evolution of the magnetic correlations along the nodal direction of the Brillouin zone in ${\mathrm{La}}_{2-x}{\mathrm{Sr}}_{x}{\mathrm{CuO}}_{4}$, spanning the doping phase diagram …

[Phys. Rev. B 95, 075139] Published Tue Feb 21, 2017

]]>Doping silicon nanocrystals (Si NCs) embedded in silicon dioxide ($\mathrm{Si}{\mathrm{O}}_{2}$) with boron (B) and phosphorus (P) is a promising way of tuning the properties of Si NCs. Here we take advantage of density functional theory to investigate the dependence of the structural and electronic properties of Si NCs emb…

[Phys. Rev. B 95, 075307] Published Tue Feb 21, 2017

]]>We present a detailed investigation of ultrafast (subpicosecond) exciton dynamics in the lattice model of a donor/acceptor heterojunction. Exciton generation by means of a photoexcitation, exciton dissociation, and further charge separation are treated on equal footing. The experimentally observed p…

[Phys. Rev. B 95, 075308] Published Tue Feb 21, 2017

]]>We investigate the occurrence of magnetic and charge density wave instabilities in rhombohedral-stacked multilayer (three to eight layers) graphene by first principles calculations including exact exchange. Neglecting spin polarization, an extremely flat surface band centered at the special point $\mathbf{K}$ …

[Phys. Rev. B 95, 075422] Published Tue Feb 21, 2017

]]>Motivated by recent studies that reported the successful synthesis of monolayer $\mathrm{Mg}{\left(\mathrm{OH}\right)}_{2}$ [Suslu *et al.*, Sci. Rep. **6**, 20525 (2016)] and hexagonal $\left(h\text{\u2212}\right)\text{AlN}$ [Tsipas *et al.*, Appl. Phys. Lett. **103**, 251605 (2013)], we investigate structural, electronic, and optical properties of vertically stacked $h$-AlN a…

[Phys. Rev. B 95, 075423] Published Tue Feb 21, 2017

]]>A single metallic slit is the simplest plasmonic structure for basic physical understanding of electromagnetic field confinement. By reducing the gap size, the field enhancement is expected to first go up and then go down when the gap width becomes subnanometer because of the quantum tunneling effec…

[Phys. Rev. B 95, 075424] Published Tue Feb 21, 2017

]]>Suppression of electron motion under an alternating current (ac) electric field is examined in a one-dimensional Hubbard model. Utilizing three complementary calculation methods, it is found unambiguously that magnitudes of the kinetic-energy suppressions are influenced sensitively by the Coulomb in…

[Phys. Rev. B 95, 085123] Published Tue Feb 21, 2017

]]>We investigate the behavior of identical dipolar fermions with aligned dipole moments in two-dimensional multilayers at zero temperature. We consider density instabilities that are driven by the attractive part of the dipolar interaction and, for the case of bilayers, we elucidate the properties of …

[Phys. Rev. B 95, 085124] Published Tue Feb 21, 2017

]]>Using polarization-resolved electronic Raman scattering we study underdoped, optimally doped, and overdoped ${\mathrm{Ba}}_{1-x}{\mathrm{K}}_{x}{\mathrm{Fe}}_{2}{\mathrm{As}}_{2}$ samples in the normal and superconducting states. We show that low-energy nematic fluctuations are universal for all studied doping ranges. In the superconducting state, we obser…

[Phys. Rev. B 95, 085125] Published Tue Feb 21, 2017

]]>Spin-orbit coupling in organic crystals is responsible for many spin-relaxation phenomena, going from spin diffusion to intersystem crossing. With the goal of constructing effective spin-orbit Hamiltonians to be used in multiscale approaches to the thermodynamical properties of organic crystals, we …

[Phys. Rev. B 95, 085126] Published Tue Feb 21, 2017

]]>We study second-harmonic generation in centrosymmetric Weyl semimetal with broken time reversal symmetry. We calculate electric current density at the double frequency of the propagating electromagnetic field in the presence of an applied constant magnetic field, using the method of kinetic equation…

[Phys. Rev. B 95, 085127] Published Tue Feb 21, 2017

]]>We investigate the $\mathrm{SU}\left(2N\right)$ symmetry effects with $2N>2$ on the two-dimensional interacting Dirac fermions at finite temperatures, including the valence-bond-solid transition, the Pomeranchuk effect, the compressibility, and the uniform spin susceptibility, by performing the determinant quantum Monte…

[Phys. Rev. B 95, 085128] Published Tue Feb 21, 2017

]]>We report first-principles calculations for one of the few materials that is believed to be a ferroelectric ferromagnet, ${\mathrm{Bi}}_{2}{\mathrm{NiMnO}}_{6}$. Our calculations show that, contrary to what has been reported so far, bulk ${\mathrm{Bi}}_{2}{\mathrm{NiMnO}}_{6}$ does not have a polarization. Instead, like ${\mathrm{BiMnO}}_{3}$, it crystallizes into a centros…

[Phys. Rev. B 95, 085129] Published Tue Feb 21, 2017

]]>The coupling between the electrical transport properties of $\mathrm{L}{\mathrm{a}}_{2/3}\mathrm{S}{\mathrm{r}}_{1/3}\mathrm{Mn}{\mathrm{O}}_{3}$ (LSMO) thin films and structural phase transitions of $\mathrm{SrTi}{\mathrm{O}}_{3}$ (STO) substrates at ${T}_{\mathrm{s}}=105\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ has been investigated. We found that the electrical resistivity of LSMO films exhibit a “cusp” at ${T}_{\mathrm{s}}$, which is greatly amplified by tuni…

[Phys. Rev. B 95, 085130] Published Tue Feb 21, 2017

]]>Charge ordering in the quasi-one-dimensional organic conductors ${\left(\mathrm{TMTTF}\right)}_{2}X\phantom{\rule{0.16em}{0ex}}\left(X=\mathrm{Sb}{\mathrm{F}}_{6},\mathrm{As}{\mathrm{F}}_{6},\mathrm{P}{\mathrm{F}}_{6}\right)$ was studied by using Raman spectroscopy. In the charge-ordered phase three vibrational features related to the ring breathing mode ${\nu}_{10}\left({a}_{g}\right)$ of neutral ($\mathrm{TMTT}{\mathrm{F}}^{0}$) and ionized ($\mathrm{TMTT}{\mathrm{F}}^{+0.5}$ and $\mathrm{TMTT}{\mathrm{F}}^{+1}$) are observed a…

[Phys. Rev. B 95, 085205] Published Tue Feb 21, 2017

]]>Quantum corrections to charge transport can give rise to an oscillatory magnetoconductance, typically observed in mesoscopic samples with a length shorter than or comparable to the phase coherence length. Here, we report the observation of magnetoconductance oscillations periodic in magnetic field w…

[Phys. Rev. B 95, 085206] Published Tue Feb 21, 2017

]]>