A systematic *ab initio* study of the influence of local magnetism on the generalized stacking fault energy (GSFE) surface in pure *fcc* iron at 0 K has been performed. In the calculations we considered ferro- and antiferro- (single- and double-layer) magnetic order of local moments as well as their com…

[Phys. Rev. B 93, 214115] Published Wed Jun 29, 2016

]]>We present a model of the lattice dynamics of the rare-earth titanate pyrochlores ${R}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ $(R=\mathrm{Tb},\text{Dy},\text{Ho})$, which are important materials in the study of frustrated magnetism. The phonon modes are obtained by density functional calculations, and these predictions are verified by comparison with scatteri…

[Phys. Rev. B 93, 214308] Published Wed Jun 29, 2016

]]>[Phys. Rev. B 93, 219904] Published Wed Jun 29, 2016

]]>[Phys. Rev. B 93, 219905] Published Wed Jun 29, 2016

]]>[Phys. Rev. B 93, 219906] Published Wed Jun 29, 2016

]]>We combine the ideas of intensity interferometry, polarization optics, and Bell's measurement into an experimental proposal which is hosted in a $\nu =2$ quantum Hall (QH) edge state. Our interferometer comprises of a single gate, that separates the spin-resolved edge states of $\nu =2$ state. An analog of wa…

[Phys. Rev. B 93, 220101(R)] Published Wed Jun 29, 2016

]]>We define the entropy operator as the negative of the logarithm of the density matrix, give a prescription for extracting its thermodynamically measurable part, and discuss its dynamics. For an isolated system we derive the first, second, and third laws of thermodynamics. For weakly coupled subsyste…

[Phys. Rev. B 93, 224305] Published Wed Jun 29, 2016

]]>We introduce a two-orbital Hamiltonian on a square lattice that contains on-site attractive interactions involving the two ${e}_{g}$ orbitals. Via a canonical mean-field procedure similar to the one applied to the well-known negative-$U$ Hubbard model, it is shown that the model develops $d$-wave (${B}_{1g}$) superco…

[Phys. Rev. B 93, 224519] Published Wed Jun 29, 2016

]]>We analyze the impact of strong correlations on the surface states of a three-dimensional topological Kondo insulator. An important observation is that correlations are strongly increased at the surface, which leads to an energetical confinement of the surface $f$ electrons into a narrow window around…

[Phys. Rev. B 93, 235159] Published Wed Jun 29, 2016

]]>We study the quantum fidelity (ground-state overlap) near quantum phase transitions of the Ising universality class in one-dimensional (1D) systems of finite-size $L$. Prominent examples occur in magnetic systems (e.g., spin-Peierls, the anisotropic $XY$ model) and in 1D topological insulators of any to…

[Phys. Rev. B 93, 235160] Published Wed Jun 29, 2016

]]>We study spin-orbit torques and charge pumping in magnetic quasi-one-dimensional zigzag nanoribbons with a hexagonal lattice, in the presence of large intrinsic spin-orbit coupling. Such a system experiences a topological phase transition from a trivial band insulator to a quantum spin Hall insulato…

[Phys. Rev. B 93, 235317] Published Wed Jun 29, 2016

]]>Atomistic details of the interaction of impurities with quasi-one-dimensional charge density wave (CDW) are revealed by scanning tunneling microscopy. Oxygen and pentacene adsorbates are utilized as strongly and weakly interacting impurities, respectively, on the well-known CDW state of the In atomi…

[Phys. Rev. B 93, 235448] Published Wed Jun 29, 2016

]]>We calculate the nonsymmetrized current noise in a quantum dot connected to two reservoirs by using the nonequilibrium Green function technique. We show that both the current autocorrelator (inside a single reservoir) and the current cross-correlator (between the two reservoirs) are expressed in ter…

[Phys. Rev. B 93, 235449] Published Wed Jun 29, 2016

]]>We study a single-mode cavity weakly coupled to a voltage-biased quantum point contact. In a perturbative analysis, the lowest order predicts a thermal state for the cavity photons, driven by the emission noise of the conductor. The cavity is thus emptied as all transmission probabilities of the qua…

[Phys. Rev. B 93, 235450] Published Wed Jun 29, 2016

]]>Two-dimensional (2D) topological insulators (TIs) are recently recognized states of quantum matter that are highly interesting for lower-power-consuming electronic devices owing to their nondissipative transport properties protected from backscattering. So far, only few 2D TIs, suffering from small …

[Phys. Rev. B 93, 235451] Published Wed Jun 29, 2016

]]>Diffusion Monte Carlo (DMC) simulations for fermions are becoming the standard for providing high-quality reference data in systems that are too large to be investigated via quantum chemical approaches. DMC with the fixed-node approximation relies on modifications of the Green's function to avoid si…

[Phys. Rev. B 93, 241118(R)] Published Wed Jun 29, 2016

]]>By means of first-principles calculations, we predict two new types of partially hydrogenated graphene systems: ${\mathrm{C}}_{6}{\mathrm{H}}_{1}$ and ${\mathrm{C}}_{6}{\mathrm{H}}_{5}$, which are shown to be a ferromagnetic (FM) semimetal and a FM narrow-gap semiconductor, respectively. When properly doped, the Fermi surface of the two systems consists of a…

[Phys. Rev. B 93, 241410(R)] Published Wed Jun 29, 2016

]]>Calculations of the electronic and magnetic properties of the nonmagnetic metallic compound ${\mathrm{YFe}}_{2}{\mathrm{Si}}_{2}$ are reported. These predict at the density functional level a magnetic state involving ordering along the $c$ axis. This predicted ground state contrasts with experiment, which does not show magnetic or…

[Phys. Rev. B 93, 245155] Published Wed Jun 29, 2016

]]>We provide a full derivation of Laughlin's Jastrow-type wave functions for quantized Hall states subject to periodic boundary conditions using an operator formalism. The construction includes the quasihole and the technically more challenging quasielectron excitation, which was left as an open probl…

[Phys. Rev. B 93, 245156] Published Wed Jun 29, 2016

]]>The interplay between charge and spin degrees of freedom in strongly correlated fermionic systems, in particular of Dirac fermions, is a long-standing problem in condensed matter physics. We investigate the competing orders in the half-filled $\mathrm{SU}\left(2N\right)$ Hubbard model on a honeycomb lattice, which can be…

[Phys. Rev. B 93, 245157] Published Wed Jun 29, 2016

]]>Using a four-band Hamiltonian, we study the phase boundary of spin-polarized-current state (SPCS) of interacting electrons in bilayer graphene. The model of spin-polarized-current state has previously been shown to resolve a number of experimental puzzles in bilayer graphene. The phase boundaries of…

[Phys. Rev. B 93, 245158] Published Wed Jun 29, 2016

]]>Time-resolved intensity cross-correlation measurements of radiative cascades are used for studying nonradiative relaxation processes of excited carriers confined in semiconductor quantum dots. We spectrally identify indirect radiative cascades which include intermediate phonon-assisted relaxations. …

[Phys. Rev. B 93, 245437] Published Wed Jun 29, 2016

]]>Pressure-dependent powder x-ray diffraction, Raman spectroscopy, and dielectric constant measurements are performed on 0.$65{\mathrm{BiFeO}}_{3}\text{\u2212}0.35{\mathrm{PbTiO}}_{3}$. Four structural transitions are reported in 0–34 GPa range. The transitions are observed at 0.7(1), 0.8(1), 3.4(1), and 6.1(1) GPa, where the system transform…

[Phys. Rev. B 93, 214114] Published Tue Jun 28, 2016

]]>We present an analytical description of localized spin-wave modes that form in a parabolic field minimum in a thin ferromagnetic film. Mode profiles proportional to Hermite functions are eigenfuctions of the applied field and exchange parts of the equations of motion, and also provide a basis for nu…

[Phys. Rev. B 93, 214436] Published Tue Jun 28, 2016

]]>Magnetic vortex is one of the simplest nontrivial topological structure that can exist in magnetic nanodots. Due to nonzero topological charge, vortices exhibit complex and interesting dynamic under external excitation, which includes excitation of translational (gyrotropic) and spin-wave modes. Here, the authors study the vortex dynamic in thick magnetic nanodots, when the vortex becomes essentially three dimensional. The third dimension is shown to lead to the appearance of additional spin-wave modes with characteristic curled structure (“curled” modes), which becomes the lowest ones in frequency among spin-wave modes for a sufficiently thick nanodot. Besides an uncommon profile, the curled modes also show uncommon hybridization with gyrotropic modes: modes propagating in opposite directions (clockwise and counterclockwise) that can be hybridized with different order gyrotropic modes.

[Phys. Rev. B 93, 214437] Published Tue Jun 28, 2016

]]>We study the zero-temperature quantum phase diagram of a spin-1 Heisenberg antiferromagnet on the honeycomb lattice with both nearest-neighbor exchange coupling ${J}_{1}>0$ and frustrating next-nearest-neighbor coupling ${J}_{2}\equiv \kappa {J}_{1}>0$, using the coupled cluster method implemented to high orders of approxim…

[Phys. Rev. B 93, 214438] Published Tue Jun 28, 2016

]]>Preparing and detecting spatially extended quantum superpositions of a massive object comprises an important fundamental test of quantum theory. These quantum states are extremely fragile and tend to quickly decay into incoherent mixtures due to the environmental decoherence. Experimental setups con…

[Phys. Rev. B 93, 214517] Published Tue Jun 28, 2016

]]>In recent years, material-induced noise arising from defects has emerged as an impediment to quantum-limited measurement in systems ranging from microwave qubits to gravity-wave interferometers. As experimental systems push to ever smaller dimensions, extrinsic system properties can affect its inter…

[Phys. Rev. B 93, 224110] Published Tue Jun 28, 2016

]]>We experimentally study the transient voltage response of yttrium iron garnet/platinum bilayer samples subject to periodic heating up to gigahertz frequencies. We observe an intrinsic cutoff frequency of the induced thermopower voltage, which characteristically depends on the thickness of the yttriu…

[Phys. Rev. B 93, 224430] Published Tue Jun 28, 2016

]]>We show clear evidence of a quadratic speedup of a quantum annealing (QA) Schrödinger dynamics over a Glauber master equation simulated annealing (SA) for a random Ising model in one dimension, via an equal-footing exact deterministic dynamics of the Jordan-Wigner fermionized problems. This is remar…

[Phys. Rev. B 93, 224431] Published Tue Jun 28, 2016

]]>Magnetic tunnel junctions are under active consideration owing to their applications including the potential next generations of spin transfer torque memories. In view of the high symmetry of the magnetic properties and of the high frequency of the system eigenexcitations, out-of-plane magnetized systems are thought to enable a faster and simpler spin-torque-induced switching process than the formerly used in-plane magnetized systems. Unfortunately, the lack of high frequency and low current switching experiments have precluded, so far, the assessment of the speed potential of perpendicular anisotropy systems at low junction dimensions. By time resolving the switching and evidencing its stochastic aspects at the nanosecond-scale, the authors here demonstrate that a complex dynamics happens and persists down to small sized elements with always a very strong asymmetry between the two switching directions. The reversal is explained by the complex interplay between the spatial profile of the stray field emanating from the fixed system of the tunnel junction and the constraint that the switching is preferably initiated from the device edge.

[Phys. Rev. B 93, 224432] Published Tue Jun 28, 2016

]]>We propose and analyze a quantum electromechanical system composed of a monolithic quartz bulk acoustic wave oscillator coupled to a superconducting transmon qubit via an intermediate $LC$ electrical circuit. Monolithic quartz oscillators offer unprecedentedly high effective masses and quality factors…

[Phys. Rev. B 93, 224518] Published Tue Jun 28, 2016

]]>A semiclassical quantization condition is derived for Landau levels in general spin-orbit coupled systems. This generalizes the Onsager quantization condition via a matrix-valued phase which describes spin dynamics along the classical cyclotron trajectory. We discuss measurement of the matrix phase …

[Phys. Rev. B 93, 235316] Published Tue Jun 28, 2016

]]>The impact of the electron-electron Coulomb interaction on the optical conductivity of graphene has led to a controversy that calls into question the universality of collisionless transport in this and other Dirac materials. Using a lattice calculation that avoids divergences present in previous nod…

[Phys. Rev. B 93, 235447] Published Tue Jun 28, 2016

]]>We investigate the possibility of creating X waves, or localized wave packets, in resonantly excited exciton-polariton superfluids. We demonstrate the existence of X-wave traveling solutions in the coupled exciton-photon system past the inflection point, where the effective mass of lower polaritons …

[Phys. Rev. B 93, 245310] Published Tue Jun 28, 2016

]]>The Peltier effect and the Ettingshausen effect are investigated in graphene nanoribbons, where charge current produces heat current along the longitudinal direction in the former case, and longitudinal charge current generates transverse heat current in the latter case. With the aid of the nonequil…

[Phys. Rev. B 93, 245432] Published Tue Jun 28, 2016

]]>We study the quantum Hall effect of two-dimensional electron gas in black phosphorus in the presence of perpendicular electric and magnetic fields. In the absence of a bias voltage, the external magnetic field leads to a quantization of the energy spectrum into equidistant Landau levels, with differ…

[Phys. Rev. B 93, 245433] Published Tue Jun 28, 2016

]]>Recent studies have focused on laser-induced gaps in graphene which have been shown to have a topological origin, thereby hosting robust states at the sample edges. While the focus has remained mainly on these topological chiral edge states, the Floquet bound states around defects lack a detailed st…

[Phys. Rev. B 93, 245434] Published Tue Jun 28, 2016

]]>*Ab initio* molecular dynamics with electronic friction (AIMDEF) is a valuable methodology to study the interaction of atomic particles with metal surfaces. This method, in which the effect of low-energy electron-hole (*e-h*) pair excitations is treated within the local density friction approximation (L…

[Phys. Rev. B 93, 245435] Published Tue Jun 28, 2016

]]>The effect of dc electric field on transport of highly mobile two-dimensional electrons is studied in wide GaAs single quantum wells placed in titled magnetic fields. The study shows that in perpendicular magnetic field resistance oscillates due to electric-field induced Landau-Zener transitions bet…

[Phys. Rev. B 93, 245436] Published Tue Jun 28, 2016

]]>The elusive structure of compressed, melt-quenched ${\mathrm{As}}_{2}{\mathrm{Se}}_{3}$ was studied in both its liquid and amorphous form up to $4.4$ and 30 GPa, respectively, by means of x-ray absorption spectroscopy and diffraction. The evolution of the short-range structure is studied by As and Se multiple $K$-edge extended x-ray…

[Phys. Rev. B 93, 214205] Published Mon Jun 27, 2016

]]>Occurrence of the topological Anderson insulator (TAI) in a HgTe quantum well suggests that when time-reversal symmetry (TRS) is maintained, the pertinent topological phase transition, marked by re-entrant $2{e}^{2}/h$ quantized conductance contributed by helical edge states, is driven by disorder. Here we…

[Phys. Rev. B 93, 214206] Published Mon Jun 27, 2016

]]>Much interest has emerged in the realization of materials with quantum spin liquid ground states, which would provide fertile ground for realizing exotic excitations. Three “Kitaev” spin liquid candidate materials have been proposed – Na${}_{2}$IrO${}_{3}$, $\alpha $-RuCl${}_{3}$, and $\alpha $-Li${}_{2}$IrO${}_{3}$ – and there has been many diverging proposals for the most relevant interactions. Here, the authors re-evaluate carefully the magnetic interactions in these materials, using nonperturbative exact diagonalization methods. The results clarify misconceptions in the literature and help estimate the potential for realizing the spin liquid state in real materials.

[Phys. Rev. B 93, 214431] Published Mon Jun 27, 2016

]]>We present an in-depth study of the magnetic properties of the spin-1 antiferromagnet 6HB-${\mathrm{Ba}}_{3}{\mathrm{NiSb}}_{2}{\mathrm{O}}_{9}$. $\mu \mathrm{SR}$ measurements demonstrate that this material shows no static magnetism down to temperatures as low as 20 mK, making it a likely candidate for a quantum spin liquid state. ${}^{121}\mathrm{Sb}$ NMR shift measurem…

[Phys. Rev. B 93, 214432] Published Mon Jun 27, 2016

]]>We show the possibility of long-range ferrimagnetic ordering with a saturation magnetization of $\sim 1{\mu}_{B}$ per spin for arbitrarily low concentration of magnetic impurities in semiconductors, provided that the impurities form a superstructure satisfying the conditions of the Lieb-Mattis theorem. Explicit …

[Phys. Rev. B 93, 214433] Published Mon Jun 27, 2016

]]>Crossed magnetic responses between spin and orbital angular momentum are studied in time-reversal-symmetric topological insulators. Due to spin-orbit coupling in the quantum spin Hall systems and three-dimensional topological insulators, the magnetic susceptibility has crossed (intersectional) compo…

[Phys. Rev. B 93, 214434] Published Mon Jun 27, 2016

]]>A spin-rotational-invariant approach to the spin-fluctuation theory of itinerant-electron magnetism is proposed and evaluated in the framework of a $d$-band model Hamiltonian including intra-atomic exchange interactions $J$ and the coupling to a local magnetic field $B$. Using a vector-field Hubbard-Strat…

[Phys. Rev. B 93, 214435] Published Mon Jun 27, 2016

]]>The role of spin-orbit coupling (SOC) in 4$d$ and 5$d$ transition metal oxides is relatively poorly understood outside of the LS or JJ coupling limits. In this work, the importance of the intermediate regime is demonstrated through the identification of SOC as an essential feature of the collective properties in nominally orbitally quenched 5${d}^{3}$ systems. The authors probe the magnetic excitations in model system Sr${}_{2}$ScOsO${}_{6}$ via inelastic neutron scattering and model the results including the effects of SOC-induced anisotropy. Experimentally determining the strengths of nearest and next-nearest neighbor interactions leads to the important discovery that the magnetic ground state is controlled by anisotropy, which would not be possible in the LS coupling limit. This indicates that SOC plays a key role in relieving frustration and promoting heightened transition temperatures in 5${d}^{3}$ double perovskites.

[Phys. Rev. B 93, 220408(R)] Published Mon Jun 27, 2016

]]>Many grain boundaries (GBs) in crystalline materials develop highly disordered, liquidlike structures at high temperatures. In alloys, this premelting effect can be fueled by solute segregation and can occur at lower temperatures than in single-component systems. A premelted GB can be modeled by a t…

[Phys. Rev. B 93, 224108] Published Mon Jun 27, 2016

]]>Pressure-induced transitions from ordered intermetallic phases to substitutional alloys to semi-ordered phases were studied in a series of bismuth tellurides. By using angle-dispersive x-ray diffraction, the compounds ${\mathrm{Bi}}_{4}{\mathrm{Te}}_{5}$, BiTe, and ${\mathrm{Bi}}_{2}\mathrm{Te}$ were observed to form alloys with the disordered body-cent…

[Phys. Rev. B 93, 224109] Published Mon Jun 27, 2016

]]>Damping, representing the loss of magnetic energy from the electrons to the lattice through the spin-orbit interaction, is calculated for Co/Pt and Co/Pd superlattices grown along the (001), (111), and (011) orientations. The damping consists of two contributions: interfacial and, usually, bulk. The…

[Phys. Rev. B 93, 224426] Published Mon Jun 27, 2016

]]>The spin torque in magnetic tunnel junctions possesses two components that both depend on the applied voltage. Here, we develop a method for the accurate extraction of this bias dependence from experiments over large voltage ranges. We study several junctions with different magnetic layer structure…

[Phys. Rev. B 93, 224427] Published Mon Jun 27, 2016

]]>Recent experiments on isolated Co clusters have shown huge orbital magnetic moments in comparison with their bulk and surface counterparts. These clusters hence provide the unique possibility to study the evolution of the orbital magnetic moment with respect to the cluster size and how competing int…

[Phys. Rev. B 93, 224428] Published Mon Jun 27, 2016

]]>The so-called Arrott plot, which consists in plotting $H/M$ against ${M}^{2}$, with $H$ the applied magnetic field and $M$ the magnetization, is used to extract valuable information in second-order magnetic phase transitions. Besides, it is widely accepted that a negative slope in the Arrott plot is indicative o…

[Phys. Rev. B 93, 224429] Published Mon Jun 27, 2016

]]>We study the spin-1/2 Heisenberg antiferromagnet on a bilayer honeycomb lattice including interlayer frustration. Using a set of complementary approaches, namely, Schwinger bosons, dimer series expansion, bond operators, and exact diagonalization, we map out the quantum phase diagram. Analyzing grou…

[Phys. Rev. B 93, 235150] Published Mon Jun 27, 2016

]]>We study systems that are close to or within the many-body localized (MBL) regime and are driven by a strong electric field. In the ergodic regime, the disorder extends the applicability of the equilibrium linear-response theory to stronger drivings, whereas the response of the MBL systems is very d…

[Phys. Rev. B 93, 235151] Published Mon Jun 27, 2016

]]>Motivated by the particle-hole symmetry at the half-filled lowest Landau level, many articles have taken the point of view, following D. T. Son, that composite fermions are Dirac particles and their Fermi sea is akin to that occurring at the surface of a three dimensional topological insulator. This presents a paradox, because the microscopic theory of composite fermions, which treats composite fermions as non-relativistic particles, has been confirmed in great detail. The authors discuss what features of the Dirac-composite fermion view can be reconciled with the microscopic theory. They also show how particle-hole symmetry can emerge in the Chern-Simons formulation of composite fermions.

[Phys. Rev. B 93, 235152] Published Mon Jun 27, 2016

]]>We derive electronic structure models for weakly interacting bilayers such as graphene-graphene and graphene–hexagonal boron nitride, based on density functional theory calculations followed by Wannier transformation of electronic states. These transferable interlayer coupling models can be applied …

[Phys. Rev. B 93, 235153] Published Mon Jun 27, 2016

]]>We study the quasiparticle properties of two-dimensional massless Dirac fermions when the many-body states possess a finite momentum density in the clean limit. The lack of Galilean invariance endows the many-body states at finite momentum density with qualitative differences from those of the syste…

[Phys. Rev. B 93, 235154] Published Mon Jun 27, 2016

]]>We discover a pair of stable three-dimensional (3D) Dirac points, a 3D photonic analog of graphene, in all-dielectric photonic crystals using structures commensurate with nanofabrication for visible-frequency photonic applications. The Dirac points carry nontrivial ${Z}_{2}$ topology and emerge for a large…

[Phys. Rev. B 93, 235155] Published Mon Jun 27, 2016

]]>It is known that metamaterial properties may differ significantly from the predictions of effective-medium theory. In many cases this is due to the finite size and discrete structure, which cannot be neglected in practical samples with a relatively small amount of elements. We analyze the response o…

[Phys. Rev. B 93, 235156] Published Mon Jun 27, 2016

]]>The orthorhombic perovskite $\mathrm{SrIr}{\mathrm{O}}_{3}$ is a semimetal, an intriguing exception in iridates where the strong spin-orbit interaction coupled with electron correlations tends to impose an insulating state. We report results of our investigation of bulk single-crystal $\mathrm{S}{\mathrm{r}}_{0.94}\mathrm{I}{\mathrm{r}}_{0.78}{\mathrm{O}}_{2.68}$ or Ir-deficient, orth…

[Phys. Rev. B 93, 235157] Published Mon Jun 27, 2016

]]>We experimentally investigated conductivity and mobility of poly(3-hexylthiophene) (P3HT) doped with tetrafluorotetracyanoquinodimethane $\left({\mathrm{F}}_{4}\mathrm{TCNQ}\right)$ for various relative doping concentrations ranging from ultralow $\left({10}^{-5}\right)$ to high $\left({10}^{-1}\right)$ and various active layer thicknesses. Although the measured conduct…

[Phys. Rev. B 93, 235203] Published Mon Jun 27, 2016

]]>We investigate the influence of inhomogeneous broadening on the optical polarization properties of high-inclination semipolar and nonpolar ${\mathrm{In}}_{x}{\mathrm{Ga}}_{1-x}\mathrm{N}$/GaN quantum wells. Different planar m-plane and $\left(20\overline{2}\overline{1}\right)$ samples were grown (including core-shell microrods) and have been characterized by excitation-…

[Phys. Rev. B 93, 235314] Published Mon Jun 27, 2016

]]>In the quantum anomalous Hall effect, chiral edge modes are expected to conduct spin polarized current without dissipation and thus hold great promise for future electronics and spintronics with low energy consumption. However, spin polarization of chiral edge modes has never been established in exp…

[Phys. Rev. B 93, 235315] Published Mon Jun 27, 2016

]]>The electronic structure of bilayer graphene under pressure develops very interesting features with an enhancement of the trigonal warping and a splitting of the parabolic touching bands at the K point of the reciprocal space into four Dirac cones, one at K and three along the T symmetry lines. As p…

[Phys. Rev. B 93, 235443] Published Mon Jun 27, 2016

]]>Atomic nanowires on semiconductor surfaces induced by the adsorption of metallic atoms have attracted a lot of attention as possible hosts of the elusive, one-dimensional Tomonaga-Luttinger liquid. The Au/Ge(100) system in particular is the subject of controversy as to whether the Au-induced nanowir…

[Phys. Rev. B 93, 235444] Published Mon Jun 27, 2016

]]>Surface reactivity is important in modifying the physical and chemical properties of surface-sensitive materials, such as the topological insulators. Even though many studies addressing the reactivity of topological insulators towards external gases have been reported, it is still under heavy debate…

[Phys. Rev. B 93, 235445] Published Mon Jun 27, 2016

]]>Using state-of-the-art many-body Green's function calculations based on the *GW* plus cumulant approach, we analyze the properties of plasmon satellites in the electron spectral function resulting from electron-plasmon interactions in one-, two-, and three-dimensional systems. Specifically, we show ho…

[Phys. Rev. B 93, 235446] Published Mon Jun 27, 2016

]]>Nodal superconductivity is observed in LiFeP while its counterpart LiFeAs with similar topology and orbital content of the Fermi surfaces is a nodeless superconductor. We explain this difference by solving, in the two-Fe Brillouin zone, the frequency-dependent Eliashberg equations with the spin-fluc…

[Phys. Rev. B 93, 241116(R)] Published Mon Jun 27, 2016

]]>Three-dimensional topological Dirac semimetals represent a novel state of quantum matter with exotic electronic properties, in which a pair of Dirac points with a linear dispersion along all momentum directions exists in the bulk. Herein, by using first-principles calculations, we discover the metas…

[Phys. Rev. B 93, 241117(R)] Published Mon Jun 27, 2016

]]>Phases of matter are traditionally seen as families of static systems exhibiting the same long-distance and low-energy correlations. In this work, the authors propose and classify a new family of phases of matter. They are novel insofar as they are intrinsically driven and out of equilibrium — they can only be realized in systems with time-dependent Hamiltonians. The phases we consider arise in 1D periodically driven systems, in the presence of strong disorder and interactions, and are similar to but qualitatively distinct from the symmetry-protected topological phases now well known in the equilibrium setting. In a companion paper, the authors examine similar intrinsically driven families of states with long-range order, and an order parameter that oscillates at a frequency that is robustly an integer multiple of the underlying drive frequency.

[Phys. Rev. B 93, 245145] Published Mon Jun 27, 2016

]]>Recent work suggests that a sharp definition of “phase of matter” can be given for periodically driven “Floquet” quantum systems exhibiting many-body localization. In this work, we propose a classification of the phases of interacting Floquet localized systems with (completely) spontaneously broken …

[Phys. Rev. B 93, 245146] Published Mon Jun 27, 2016

]]>The photoelectron spin polarization in angle-resolved photoemission from the topological surface state in ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$(0001) has been investigated in a combined experimental and theoretical study. Our measurements show significant photon-energy-dependent deviations in the three-dimensional spin polarizati…

[Phys. Rev. B 93, 245150] Published Mon Jun 27, 2016

]]>Duality is a powerful theoretical tool whereby the strongly interacting and intractable regime of a theory can be accessed in terms of weakly interacting “dual” variables. In condensed matter, this is familiar from the Kramers-Wannier duality of the Ising model, and boson-vortex duality. Here, a duality for another fundamental problem – Dirac fermions in two spatial dimensions – is obtained, which provides a new window to the physics of strongly interacting electrons. This leads to unexpected connections between topological insulators in three dimensions and the physics of the half-filled Landau level, including composite fermions and Pfaffian quantum Hall states.

[Phys. Rev. B 93, 245151] Published Mon Jun 27, 2016

]]>We report a structural study of the Weyl semimetals TaAs and TaP, utilizing diffraction and imaging techniques, where we show that they contain a high density of defects, leading to nonstoichiometric single crystals of both semimetals. Despite the observed defects and nonstoichiometry on samples gro…

[Phys. Rev. B 93, 245152] Published Mon Jun 27, 2016

]]>Inspired by the recent experimental signatures of relativistic hydrodynamics in graphene, we investigate theoretically the behavior of hydrodynamic sound modes in such quasirelativistic fluids near charge neutrality, within linear response. Locally driving an electron fluid at a resonant frequency t…

[Phys. Rev. B 93, 245153] Published Mon Jun 27, 2016

]]>We consider the interacting Aubry-André model describing fermions on a one-dimensional lattice with an incommensurate potential and a short-range many-body interaction. The single-particle spectrum has infinitely many gaps in the extended phase and at zero temperature is an insulator for almost all …

[Phys. Rev. B 93, 245154] Published Mon Jun 27, 2016

]]>Thermoelectric materials utilize the Seebeck effect to convert heat to electrical energy. The Seebeck coefficient (thermopower), $S$, depends on the free (mobile) carrier concentration, $n$, and effective mass, ${m}^{*}$, as $S\sim {m}^{*}/{n}^{2/3}$. The carrier concentration in tellurides can be derived from ${}^{125}\mathrm{Te}$ nuclear m…

[Phys. Rev. B 93, 245202] Published Mon Jun 27, 2016

]]>We consider a system of weakly coupled wires with quantum Hall effect (QHE) and in the presence of a spatially periodic modulation of the chemical potential along the wire, equivalent to a charge density wave (CDW). We investigate the competition between the two effects which both open a gap. We sho…

[Phys. Rev. B 93, 245308] Published Mon Jun 27, 2016

]]>We study potential scattering in a two-dimensional electron gas with Rashba spin-orbit coupling in the limit that the energy of the scattering electron approaches the bottom of the lower spin-split band. Focusing on two spin-independent circularly symmetric potentials, an infinite barrier and a delt…

[Phys. Rev. B 93, 245309] Published Mon Jun 27, 2016

]]>Doping graphene by heteroatoms such as nitrogen presents an attractive route to control the position of the Fermi level in the material. We prepared N-doped graphene on Cu(111) and Ir(111) surfaces via chemical vapor deposition of two different molecules. Using scanning tunneling microscopy images a…

[Phys. Rev. B 93, 245430] Published Mon Jun 27, 2016

]]>We discuss electronic and ionic defect concentration profiles at the conducting interface between the two wide-band-gap insulators ${\mathrm{LaAlO}}_{3}$ and ${\mathrm{SrTiO}}_{3}$ (STO). The profiles are deduced from a thermodynamic model considering a local space charge layer (SCL) originating from charge transfer to the interfa…

[Phys. Rev. B 93, 245431] Published Mon Jun 27, 2016

]]>This study reports experimental, computational, and theoretical evidence for a previously unobserved coherent phonon-phonon interaction in an organic solid that can be described by the application of Fano's analysis to a case without the presence of a continuum. Using Raman spectroscopy of the hydro…

[Phys. Rev. B 93, 214307] Published Fri Jun 24, 2016

]]>We study how the Rashba spin-orbit interaction influences unconventional superconductivity in a two-dimensional electron gas partially spin polarized by a magnetic field. Somewhat surprisingly, we find that for all field orientations, only the larger Fermi surface is superconducting. When the magnet…

[Phys. Rev. B 93, 214516] Published Fri Jun 24, 2016

]]>This study is motivated by a challenge to the third law of the thermodynamics: how does the degenerated ground state in a textbook example behave in a real compound? At very low temperatures, nature tries to preserve the basic law using small perturbations and a novel quantum state should appear. The authors here study the classic frustrated magnet Ba${}_{3}$Yb${}_{2}$Zn${}_{5}$O${}_{11}$, a spin tetrahedron having two-fold degeneracy realized in a breathing pyrochlore lattice. They measure by inelastic neutron scattering the low-energy excitations in order to identify the effective spin Hamiltonian and macroscopic properties at very low temperatures. They demonstrate how the degeneracy of the ground state is lifted and a unique quantum state is selected.

[Phys. Rev. B 93, 220407(R)] Published Fri Jun 24, 2016

]]>We develop a method to efficiently calculate trial wave functions for quantum Hall systems which involve projection onto the lowest Landau level. The method essentially replaces the lowest Landau level projection by projection onto the $M$ lowest eigenstates of a suitably chosen Hamiltonian acting wit…

[Phys. Rev. B 93, 235149] Published Fri Jun 24, 2016

]]>We have investigated the excited-state (ES) charging energies in quantum dots (QDs) by measuring a terahertz (THz)-induced photocurrent in a single-electron transistor (SET) geometry that contains a single InAs QD between metal nanogap electrodes. A photocurrent is produced in the QD SETs through TH…

[Phys. Rev. B 93, 235313] Published Fri Jun 24, 2016

]]>Graphene and carbon nanotubes have extraordinary mechanical and electronic properties. Intrinsic line defects such as local nonhexagonal reconstructions or grain boundaries, however, significantly reduce the tensile strength, but feature exciting electronic properties. Here, we address the propertie…

[Phys. Rev. B 93, 235441] Published Fri Jun 24, 2016

]]>The sequential two-photon emission process known as biexciton cascade emission is a characteristic phenomenon that occurs in photoexcited semiconductor nanocrystals (NCs). This process occurs when a biexciton state is created in the NCs; thus, the occurrence of the process is related to the photoabs…

[Phys. Rev. B 93, 235442] Published Fri Jun 24, 2016

]]>We find that the major and minor intensity lobes of a measured rotational-anisotropy pattern of optical second-harmonic generation (SHG) from a cleaved $\mathrm{B}{\mathrm{i}}_{2}\mathrm{S}{\mathrm{e}}_{3}$ (111) surface can gradually change with time and eventually switch their relative amplitudes. This switching provides a means for tracking th…

[Phys. Rev. B 93, 241308(R)] Published Fri Jun 24, 2016

]]>High-temperature superconductivity emerges upon doping a state of matter that is insulating because of interactions. A widely studied model considers one orbital per ${\mathrm{CuO}}_{2}$ unit cell on a square lattice with a strong intraorbital repulsion that leads to a so-called Mott-Hubbard insulator. Here we solv…

[Phys. Rev. B 93, 245147] Published Fri Jun 24, 2016

]]>The electronic and magnetic properties of distorted monoclinic double perovskite ${\mathrm{Sr}}_{2}{\mathrm{CeIrO}}_{6}$ were examined based on both experiments and first-principles density functional theory calculations. From the calculations we conclude that low-spin-state ${\mathrm{Ir}}^{4+}$ $\left(5{\mathit{d}}^{5}\right)$ forms a rare weakly antiferromagnetic (AFM)…

[Phys. Rev. B 93, 245148] Published Fri Jun 24, 2016

]]>Unraveling the peculiar properties of topological materials often requires tuning of the bulk chemical potential, which has been addressed by compensation of acceptors and donors. Compensation necessarily creates Coulomb disorder which, however, impedes chemical potential tuning and gives rise to self-organized charge puddles. In the topological insulator BiSbTeSe${}_{2}$, optical data and Monte Carlo simulations presented here reveal the existence of puddles at low temperatures as well as their surprising “evaporation” on a temperature scale of about 40 K. The highly nonlinear screening effect of thermal excitations is also important for Dirac matter or Weyl semimetals. Understanding and controlling the puddles will be a key to realizing novel phenomena in 3D topological materials, as was the case with 2D materials such as graphene.

[Phys. Rev. B 93, 245149] Published Fri Jun 24, 2016

]]>We have used density functional theory to investigate the dynamical stability and the electronic structure of several new semiconducting two-dimensional single layers, with chemical compositions such as ${\mathrm{AB}X}_{3}$ and ${\mathrm{A}}_{2}{X}_{3}$. The calculated interlayer binding energies and the absence of imaginary states in …

[Phys. Rev. B 93, 245307] Published Fri Jun 24, 2016

]]>Ideal graphene antidot lattices are predicted to show promising band gap behavior (i.e., ${E}_{G}\simeq 500$ meV) under carefully specified conditions. However, for the structures studied so far this behavior is critically dependent on superlattice geometry and is not robust against experimentally realistic diso…

[Phys. Rev. B 93, 245429] Published Fri Jun 24, 2016

]]>Previous theoretical studies [W. Cho, C. Platt, R. H. McKenzie, and S. Raghu, Phys. Rev. B **92**, 134514 (2015); N. Lera and J. V. Alvarez, Phys. Rev. B **92**, 174523 (2015)] have suggested that ${\mathrm{Li}}_{0.9}{\mathrm{Mo}}_{6}{\mathrm{O}}_{17}$, a quasi-one-dimensional “purple bronze” compound, exhibits spin-triplet superconductivity and that…

[Phys. Rev. B 93, 214515] Published Thu Jun 23, 2016

]]>Hydrogen insertion in the CeNiSn Kondo semiconductor induces antiferromagnetic ordering for CeNiSnH below ${T}_{N}=4.5\phantom{\rule{0.28em}{0ex}}\mathrm{K}$ whereas $\mathrm{CeNiSn}{\mathrm{H}}_{1.8}$ orders ferromagnetically below ${T}_{C}=7.0\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. We present a detailed investigation of these $\mathrm{CeNiSn}{\mathrm{H}}_{x}$ compounds by means of muon spin spectroscopy performed at both ambient an…

[Phys. Rev. B 93, 224424] Published Thu Jun 23, 2016

]]>The magnetic anisotropy energy of tetragonally distorted disordered alloys Fe ${}_{1-x}{\mathrm{Co}}_{x}$ is calculated by two different virtual crystal approximation methods and an averaged supercell method within the projected-augmented-wave (PAW) methodology and the magnetic force theorem. The details of the spin-orb…

[Phys. Rev. B 93, 224425] Published Thu Jun 23, 2016

]]>We present nuclear magnetic resonance evidence that very slow $(\le 1$ MHz) spin fluctuations persist into the overdoped regime of $\mathrm{Ba}\left({\mathrm{Fe}}_{1-x}{\mathrm{Rh}}_{x}\right){}_{2}{\mathrm{As}}_{2}$ superconductors. Measurements of the ${}^{75}\mathrm{As}$ spin echo decay rate, obtained both with Hahn Echo and Carr Purcell Meiboom Gill pulse sequences, show that the slo…

[Phys. Rev. B 93, 224517] Published Thu Jun 23, 2016

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