We study how the color and polarization of ultrashort pulses of visible light can be used to control the demagnetization processes of the antiferromagnetic insulator ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$. We utilize time-resolved second harmonic generation (SHG) to probe how changes in the magnetic and structural state evolve in t…

[Phys. Rev. B 94, 014430] Published Fri Jul 22, 2016

]]>We report magnetic susceptibility $\chi $, isothermal magnetization $M$, heat capacity ${C}_{\mathrm{p}}$, and electrical resistivity $\rho $ measurements on undoped ${\mathrm{EuMn}}_{2}{\mathrm{As}}_{2}$ and K-doped ${\mathrm{Eu}}_{0.96}{\mathrm{K}}_{0.04}{\mathrm{Mn}}_{2}{\mathrm{As}}_{2}$ and ${\mathrm{Eu}}_{0.93}{\mathrm{K}}_{0.07}{\mathrm{Mn}}_{2}{\mathrm{As}}_{2}$ single crystals with the trigonal ${\mathrm{CaAl}}_{2}{\mathrm{Si}}_{2}$-type structure as a function of temperature $T$ and magnetic f…

[Phys. Rev. B 94, 014431] Published Fri Jul 22, 2016

]]>Thermal expansion and forced magnetostriction of MnSi were measured as a function of temperature down to 5 K and magnetic field to 3 T. The small length (volume) discontinuity at the magnetic phase transition in MnSi decreases with application of magnetic field to a value $\mathrm{\Delta}L/L\sim {10}^{-7}$, and then suddenl…

[Phys. Rev. B 94, 020410(R)] Published Fri Jul 22, 2016

]]>The entanglement properties of quenched quantum systems have been studied for a decade, however, results in dimensions other than $d=1$ are generally lacking. We remedy this by investigating the entanglement properties of bosonic critical systems in $d=3$, both numerically and analytically, comparing th…

[Phys. Rev. B 94, 024306] Published Fri Jul 22, 2016

]]>To understand the interfacial scattering effect on the anomalous Hall effect (AHE), we prepared multilayers of ${\left(\mathrm{F}{\mathrm{e}}_{\left(36/n\right)\phantom{\rule{0.28em}{0ex}}\mathrm{nm}}/\mathrm{A}{\mathrm{u}}_{(12/n)\phantom{\rule{4pt}{0ex}}\mathrm{nm}}\right)}_{n}$ using an e-beam evaporator. This structure design allowed us to investigate the effect of interfacial scattering on the AHE, while keeping the samples' thickness an…

[Phys. Rev. B 94, 024428] Published Fri Jul 22, 2016

]]>The magnetic and structural properties of cobalt were investigated under high pressure (160 GPa) and low temperature (50 K), by synchrotron K-edge x-ray magnetic circular dichroism and x-ray diffraction. A quasihydrostatic equation of state was measured up to 160 GPa. We found that uniaxial stress p…

[Phys. Rev. B 94, 024429] Published Fri Jul 22, 2016

]]>${\mathrm{Re}}_{6}\mathrm{Hf}$, which crystallizes in $\alpha $-Mn structure(space group $I\overline{4}3m)$ without a spatial inversion center, is a superconductor with a superconducting transition temperature ${T}_{c}\phantom{\rule{4pt}{0ex}}\approx 6.2\phantom{\rule{4pt}{0ex}}\mathrm{K}$. The measurements of magnetic susceptibility $\left(\chi \right)$, resistivity $\left(\rho \right)$, and specific heat capacity $\left(C\right)$ were carried out. Bulk superc…

[Phys. Rev. B 94, 024518] Published Fri Jul 22, 2016

]]>We report point-contact spectroscopic studies on high quality single crystalline $\beta \text{\u2212}{\mathrm{PdBi}}_{2}$ with a superconducting ${T}_{c}=5.2\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. Our measurements show a typical double-peak structure in the voltage-biased junction conductance at low temperatures, probably excluding the existence of topological Andreev bound…

[Phys. Rev. B 94, 024519] Published Fri Jul 22, 2016

]]>It is generally believed that the interedge coupling destroys the quantum spin Hall (QSH) effect along with the gap opening at the Dirac points. Using first-principles calculations, we find that the quantized edge transport persists in the presence of interedge coupling in Ta intercalated epitaxial …

[Phys. Rev. B 94, 035147] Published Fri Jul 22, 2016

]]>We apply a generalized model for the determination and analysis of the dielectric function of optically anisotropic materials with color dispersion to phonon modes and show that it can also be generalized to excitonic polarizabilities and electronic band-band transitions. We take into account that t…

[Phys. Rev. B 94, 035148] Published Fri Jul 22, 2016

]]>In the presence of a (time-dependent) macroscopic electric field the electron dynamics of dielectrics cannot be described by the time-dependent density only. We present a real-time formalism that has the density and the macroscopic polarization $\mathcal{P}$ as key quantities. We show that a simple local functi…

[Phys. Rev. B 94, 035149] Published Fri Jul 22, 2016

]]>On the basis of many-body *ab initio* calculations, using the single-shot ${G}_{0}{W}_{0}$ method and Bethe-Salpeter equation, we study phosphorene nanoribbons (PNRs) in the two typical zigzag and armchair directions. The electronic structure, optical absorption, electron-hole (exciton) binding energy, exciton ex…

[Phys. Rev. B 94, 035437] Published Fri Jul 22, 2016

]]>Recent experiments on silicon nanostructures have seen breakthroughs toward scalable, long-lived quantum information processing. The valley degree of freedom plays a fundamental role in these devices, and the two lowest-energy electronic states of a silicon quantum dot can form a valley qubit. In th…

[Phys. Rev. B 94, 035438] Published Fri Jul 22, 2016

]]>The creation of electron-hole pairs by photoexcitation in quasi-two-dimensional semiconductor heterostructures has long provided one motivation for the study of a positive impurity immersed in an electron gas. Improved understanding of such systems is vital to realize the full potential of solar cells and optoelectronic transistors and memory devices. Collective, many-body phenomena dominate the behavior of the hole-in-electron-gas system at high carrier density, while excitonic species such as the exciton (a bound state of an electron and the hole) and the trion (a bound state formed from two electrons and the hole) emerge at low density. Confinement enhances the binding energy in quantum wells compared to bulk samples but, despite much experimental and theoretical work, the properties of excitons and trions are still uncertain. The authors perform diffusion Monte Carlo calculations of a single positive impurity immersed in a two-dimensional, paramagnetic electron gas at zero temperature using the Coulomb ($1/r$) potential. A gradual crossover from the collective, many-body behavior to the trion state is studied over a range of carrier densities and electron-hole mass ratios consistent with recent experiments in GaAs and CdTe quantum wells. Relaxation energies, electron-hole pair correlation functions, and electron-hole center-of-mass momentum densities are reported for these systems and may be used, for example, in density functional theory studies of optoelectronic devices.

[Phys. Rev. B 94, 041410(R)] Published Fri Jul 22, 2016

]]>We present measurements on gate-defined double quantum dots in Ge-Si core-shell nanowires, which we tune to a regime with visible shell filling in both dots. We observe a Pauli spin blockade and can assign the measured leakage current at low magnetic fields to spin-flip cotunneling, for which we mea…

[Phys. Rev. B 94, 041411(R)] Published Fri Jul 22, 2016

]]>Connections between the electronic eigenstates and conductivity of one-dimensional (1D) disordered systems is studied in the framework of the tight-binding model. We show that for weak disorder only part of the states exhibit resonant transmission and contribute to the conductivity. The rest of the …

[Phys. Rev. B 94, 014207] Published Thu Jul 21, 2016

]]>Frustration is often a key ingredient for reentrance mechanisms. Here we study the frustrated anisotropic shuriken Ising model, where it is possible to extend the notion of reentrance between *disordered* phases, i.e., in absence of phase transitions. By tuning the anisotropy of the lattice, we open a…

[Phys. Rev. B 94, 014429] Published Thu Jul 21, 2016

]]>Ballistic Josephson junctions are studied in the presence of a spin-splitting field and spin-orbit coupling. A generic expression for the quasiclassical Green's function is obtained and with its help we analyze several aspects of the proximity effect between a spin-textured normal metal (N) and sing…

[Phys. Rev. B 94, 014515] Published Thu Jul 21, 2016

]]>Amorphous (a)-${\mathrm{HfO}}_{2}$ is a prototype high dielectric constant insulator with wide technological applications. Using *ab initio* calculations we show that excess electrons and holes can trap in a-${\mathrm{HfO}}_{2}$ in energetically much deeper polaron states than in the crystalline monoclinic phase. The electrons and h…

[Phys. Rev. B 94, 020103(R)] Published Thu Jul 21, 2016

]]>In a wide range of experiments where electrical currents are used to inject angular momentum, or spin currents, from a metallic ferromagnet into a nonmagnetic metal, the interface plays a critical role. Whether in the giant magnetoresistance effect or in nonlocal spin valves, a loss of spin polarization of an electrical current crossing the interface is seen to reduce the spin current and lead to smaller overall response in sensors. The authors here compare electrical spin injection to the more recently discovered thermal spin injection in a nonlocal spin valve. They show that, despite a strong reduction of electrical spin injection that they tie to the loss of interfacial spin polarization, thermal spin injection remains a large effect. This highlights that thermal spin injection (also called the spin-dependent Seebeck effect) can proceed by new physical mechanisms not possible in the electrically driven case, potentially involving incoherent spin pumping and collective behavior of magnetization in the oxidized interface layer. Better understanding of these interface effects could lead to new ways to increase sensitivity of next-generation magnetic sensors and efficiency of sources of spin current in metallic systems.

[Phys. Rev. B 94, 024426] Published Thu Jul 21, 2016

]]>Magnetism is a key driving force controlling several thermodynamic and kinetic properties of Fe-Cr systems. We present a tight-binding model for Fe-Cr, where magnetism is treated beyond the usual collinear approximation. A major advantage of this model consists in a rather simple fitting procedure. …

[Phys. Rev. B 94, 024427] Published Thu Jul 21, 2016

]]>Oxygen is known to play an important role in the multiferroicity of rare earth manganites; however, how this role changes with rare earth elements is still not fully understood. To address this question, we have used resonant soft x-ray scattering spectroscopy to study the $F$-type $(0,\tau ,0)$ diffraction…

[Phys. Rev. B 94, 035145] Published Thu Jul 21, 2016

]]>We consider a class of *quantum Hall topological insulators*: topologically nontrivial states with zero Chern number at finite magnetic field, in which the counterpropagating edge states are protected by a symmetry (spatial or spin) other than time-reversal. HgTe-type heterostructures and graphene are…

[Phys. Rev. B 94, 035146] Published Thu Jul 21, 2016

]]>The Dirac electrons of graphene, an intrinsic zero gap semiconductor, uniquely carry spin and pseudospin that give rise to many fascinating electronic and transport properties. While isolated zigzag graphene nanoribbons are antiferromagnetic semiconductors, we show by means of first-principles and t…

[Phys. Rev. B 94, 035433] Published Thu Jul 21, 2016

]]>We investigate gain in microwave photonic cavities coupled to voltage-biased double quantum dot systems with an arbitrarily strong dot-lead coupling and with a Holstein-like light-matter interaction, by employing the diagrammatic Keldysh nonequilibrium Green's function approach. We compute out-of-eq…

[Phys. Rev. B 94, 035434] Published Thu Jul 21, 2016

]]>Remarkable optical and electrical properties of two-dimensional (2D) materials, such as graphene and transition-metal dichalcogenide (TMDC) monolayers, offer vast technological potential for novel and improved optoelectronic nanodevices, many of which rely on nonlinear optical effects in these 2D ma…

[Phys. Rev. B 94, 035435] Published Thu Jul 21, 2016

]]>We analyze the time-resolved energy transport and the entropy production in ac-driven quantum coherent electron systems coupled to multiple reservoirs at finite temperature. At slow driving, we formulate the first and second laws of thermodynamics valid at each instant of time. We identify heat flux…

[Phys. Rev. B 94, 035436] Published Thu Jul 21, 2016

]]>We design a Stern-Gerlach apparatus that separates quasispin components on the lattice, without the use of external fields. The effect is engineered using intrinsic parameters, such as hopping amplitudes and on-site potentials. A theoretical description of the apparatus relying on a generalized Fold…

[Phys. Rev. B 94, 045129] Published Thu Jul 21, 2016

]]>In this paper we investigate the two manganese pnictides ${\mathrm{BaMn}}_{2}{\mathrm{As}}_{2}$ and LaMnAsO, using fully charge self-consistent density functional plus dynamical mean-field theory calculations. These systems have a nominally half-filled $d$ shell, and as a consequence, electronic correlations are strong, placing th…

[Phys. Rev. B 94, 045130] Published Thu Jul 21, 2016

]]>Transition-metal dichalcogenides (TMDs) $M{X}_{2}$ $(M=\text{Ti},\text{Nb},\text{Ta};X=\text{S},\text{Se},\text{Te})$ exhibit a rich set of charge density wave (CDW) orders, which usually coexist and/or compete with superconductivity. The mechanisms of CDWs and superconductivity in TMDs are still under debate. Here we perform an investigation on a t…

[Phys. Rev. B 94, 045131] Published Thu Jul 21, 2016

]]>It is critical to capture the effect due to strain and material interface for device level transistor modeling. We introduce a transferable $s{p}^{3}{d}^{5}{s}^{*}$ tight-binding model with nearest-neighbor interactions for arbitrarily strained group IV and III-V materials. The tight-binding model is parametrized wi…

[Phys. Rev. B 94, 045311] Published Thu Jul 21, 2016

]]>We introduce a technique to calculate thermal conductivity in disordered nanostructures: a finite-difference time-domain solution of the elastic-wave equation combined with the Green-Kubo formula. The technique captures phonon wave behavior and scales well to nanostructures that are too large or too…

[Phys. Rev. B 94, 045312] Published Thu Jul 21, 2016

]]>To study the influence of microwave irradiation on two-dimensional electrons, we apply a method based on capacitance measurements in GaAs quantum well samples where the gate covers a central part of the layer. We find that the capacitance oscillations at high magnetic fields, caused by the oscillati…

[Phys. Rev. B 94, 045313] Published Thu Jul 21, 2016

]]>We determined the ground state of ${}^{4}\mathrm{He}_{N}$ clusters adsorbed on one side of graphene for selected cluster sizes in the range from $N=20$ to $N=127$. For all investigated clusters variational and diffusion Monte Carlo simulations were performed at $T=0$ K, and in addition for a selected subset finite temperatu…

[Phys. Rev. B 94, 045428] Published Thu Jul 21, 2016

]]>Based on first-principles phonon and finite temperature molecular dynamics calculations including spin-orbit coupling, we showed that free-standing single-layer phases of bismuth, namely buckled honeycomb and asymmetric washboard structures named as bismuthene, are stable at high temperature. We stu…

[Phys. Rev. B 94, 014115] Published Wed Jul 20, 2016

]]>Motivated by recent experiments on all-optical magnetization reversal in conductive ferromagnetic thin films we use nonequilibrium formalism to calculate the effective magnetic field induced in a Rashba ferromagnet by a short laser pulse. The main contribution to the effect originates in the direct …

[Phys. Rev. B 94, 014425] Published Wed Jul 20, 2016

]]>The spatial and temporal correlations of magnetic moments in the paramagnetic regime of ${\left(\mathrm{Mn},\mathrm{Fe}\right)}_{2}\left(\mathrm{P},\mathrm{Si}\right)$ have been investigated by means of polarized neutron diffraction and muon-spin relaxation techniques. Short-range magnetic correlations are present at temperatures far above the ferromagnetic trans…

[Phys. Rev. B 94, 014426] Published Wed Jul 20, 2016

]]>We report temperature-dependent spin Seebeck measurements on Pt/YIG bilayers and Pt/NiO/YIG trilayers, where YIG (yttrium iron garnet, ${\mathrm{Y}}_{3}\mathrm{F}{\mathrm{e}}_{5}{\mathrm{O}}_{12}$) is an insulating ferrimagnet and NiO is an antiferromagnet at low temperatures. The thickness of the NiO layer is varied from 0 to 10 nm. In the Pt/YIG bil…

[Phys. Rev. B 94, 014427] Published Wed Jul 20, 2016

]]>We report the discovery of the linear magnetoelectric effect in a family of spinel oxides, $\mathrm{C}{\mathrm{o}}_{3}{\mathrm{O}}_{4}$ and $\mathrm{Mn}{B}_{2}{\mathrm{O}}_{4}$ $(B=\mathrm{Al},\text{Ga})$ with simple collinear antiferromagnetic spin structure. An external magnetic field induces a dielectric anomaly at ${T}_{\mathrm{N}}$, accompanied by the generation of electric polarization that var…

[Phys. Rev. B 94, 014428] Published Wed Jul 20, 2016

]]>Using nuclear quadrupole resonance, the phase diagram of $1111R{\mathrm{FeAsO}}_{1-x}{\mathrm{F}}_{x}$ ($R=\text{La}$, Ce, Sm) iron pnictides is constructed as a function of the local charge distribution in the paramagnetic state, which features low-doping-like (LD-like) and high-doping-like (HD-like) regions. Compounds based on magneti…

[Phys. Rev. B 94, 014514] Published Wed Jul 20, 2016

]]>Impulsive optical excitation can generate both coherent and squeezed phonons through first- and second-order Raman-like processes. The expectation value of the phonon displacement $\langle {u}_{q}\rangle $ oscillates at the phonon mode frequency for the coherent state but remains zero for a pure squeezed state. In contr…

[Phys. Rev. B 94, 020302(R)] Published Wed Jul 20, 2016

]]>Magnetic orders characterized by multiple ordering vectors harbor noncollinear and noncoplanar spin textures and can be a source of unusual electronic properties through the spin Berry phase mechanism. We theoretically show that such multiple-$Q$ states are stabilized in itinerant magnets in the form …

[Phys. Rev. B 94, 024424] Published Wed Jul 20, 2016

]]>We performed micromagnetic numerical calculations to explore a cylindrical nanotube's magnetization dynamics and domain-wall (DW) motions driven by eigen-circular-rotating magnetic fields of different frequencies. We discovered the presence of two different localized DW oscillations as well as asymm…

[Phys. Rev. B 94, 024425] Published Wed Jul 20, 2016

]]>We investigate by scanning susceptibility microscopy the response of a thin Pb strip, with a square array of submicron antidots, to a low-frequency ac magnetic field applied perpendicularly to the film plane. By mapping the local permeability of the sample within the field range where vortices trapp…

[Phys. Rev. B 94, 024516] Published Wed Jul 20, 2016

]]>Superconductivity in heavy-fermion systems has an unconventional nature and is considered to originate from the universal features of the electronic structure. Here, the Anderson lattice model is studied by means of the full variational Gutzwiller wave function incorporating nonlocal effects of the …

[Phys. Rev. B 94, 024517] Published Wed Jul 20, 2016

]]>We investigate theoretically and numerically the propagation of electromagnetic waves in $PT$-symmetric periodic stacks composed of hyperbolic metamaterial layers separated by dielectric media with balanced loss and gain. We derive the characteristic frequencies governing the dispersion properties of …

[Phys. Rev. B 94, 035141] Published Wed Jul 20, 2016

]]>Recently, Strickland *et al.* [Phys. Rev. B **91**, 085104 (2015)] retrieved dynamic polarizabilities of infinitely long wires at oblique incidence, reporting nonzero magnetoelectric coupling, seemingly defying existing theorems which forbid this in centrosymmetric scatterers. We reconcile this finding w…

[Phys. Rev. B 94, 035142] Published Wed Jul 20, 2016

]]>We consider a simple conceptual question with respect to Majorana zero modes in semiconductor nanowires: can the measured nonideal values of the zero-bias-conductance-peak in the tunneling experiments be used as a characteristic to predict the underlying topological nature of the proximity induced n…

[Phys. Rev. B 94, 035143] Published Wed Jul 20, 2016

]]>We study the many-body physics of different quantum systems using a hierarchy of correlations, which corresponds to a generalization of the $1/\mathcal{Z}$ hierarchy. The decoupling scheme obtained from this hierarchy is adapted to calculate double-time Green's functions and due to its nonperturbative nature, w…

[Phys. Rev. B 94, 035144] Published Wed Jul 20, 2016

]]>We report a study on temperature-dependent resonant fluorescence from InAs/GaAs quantum dots. We combined spectral and temporal measurements in order to identify sources of dephasing. In the spectral domain, we observed temperature-dependent broadening of the zero-phonon line as $0.3\phantom{\rule{0.28em}{0ex}}\mu \mathrm{eV}/\mathrm{K}$, and a temp…

[Phys. Rev. B 94, 035432] Published Wed Jul 20, 2016

]]>We report an inelastic neutron scattering study of the spin waves of the one-dimensional antiferromagnetic spin ladder compound ${\mathrm{RbFe}}_{2}{\mathrm{Se}}_{3}$. The results reveal that the products, $SJ$'s, of the spin $S$ and the magnetic exchange interaction $J$ along the antiferromagnetic (leg) direction and the ferromagneti…

[Phys. Rev. B 94, 041111(R)] Published Wed Jul 20, 2016

]]>We propose that illumination with light provides a useful platform for creating tunable semimetals. We show that by shining light on semimetals with a line degeneracy, one can convert them to a point-node semimetal. These point nodes are adjustable, and their position can be controlled by simply rot…

[Phys. Rev. B 94, 041409(R)] Published Wed Jul 20, 2016

]]>We present a numerical study of the many-body localization (MBL) phenomenon in the high-temperature limit within an anisotropic Heisenberg model with random local fields. Taking the dynamical spin conductivity $\sigma \left(\omega \right)$ as the test quantity, we investigate the full frequency dependence of sample-to-sampl…

[Phys. Rev. B 94, 045126] Published Wed Jul 20, 2016

]]>We study parafermion chains with ${\mathbb{Z}}_{k}$ symmetry subject to a periodic binary drive, focusing on the case $k=3$. We find that the chains support different Floquet edge modes at nontrivial quasienergies, distinct from those for the static system. We map out the corresponding phase diagram by a combination …

[Phys. Rev. B 94, 045127] Published Wed Jul 20, 2016

]]>We show how to compute the electro-optical functions (absorption, reflection, and transmission) when Rydberg exciton-polaritons appear, including the effect of the coherence between the electron-hole pair and the electromagnetic field. With the use of the real density matrix approach, numerical calc…

[Phys. Rev. B 94, 045205] Published Wed Jul 20, 2016

]]>We study the dark exciton's behavior as a coherent physical two-level spin system (qubit) using an external magnetic field in the Faraday configuration. Our studies are based on polarization-sensitive intensity autocorrelation measurements of the optical transition resulting from the recombination o…

[Phys. Rev. B 94, 045426] Published Wed Jul 20, 2016

]]>Interference effects in quantum dots between different transport channels can lead to a strong suppression of conductance, which cuts like a canyon through the common conductance plot [Phys. Rev. Lett. **104**, 186804 (2010)]. In the present work we consider the thermoelectric transport properties of th…

[Phys. Rev. B 94, 045427] Published Wed Jul 20, 2016

]]>Core-shell coating structures and concentration gradient materials may enhance Li-ion battery performance by integrating advantages of core and shell components without introducing unfavorable problems associated with general coatings. The fundamental thermodynamic properties of concentration gradie…

[Phys. Rev. B 94, 014114] Published Tue Jul 19, 2016

]]>The metallic compound ${\mathrm{EuCo}}_{2}{\mathrm{P}}_{2}$ with the body-centered tetragonal ${\mathrm{ThCr}}_{2}{\mathrm{Si}}_{2}$ structure containing Eu spins-7/2 was previously shown from single-crystal neutron diffraction measurements to exhibit a helical antiferromagnetic (AFM) structure below ${T}_{\mathrm{N}}=66.5$ K with the helix axis along the $c$ axis and with th…

[Phys. Rev. B 94, 014422] Published Tue Jul 19, 2016

]]>The ultrafast demagnetization of small iron clusters initiated by an intense optical excitation is studied from the time-dependent spin density functional theory (TDSDFT). In particular we investigate the effect of the spin-orbit interaction on the onset of the demagnetization process. It is found t…

[Phys. Rev. B 94, 014423] Published Tue Jul 19, 2016

]]>We report a neutron spin-echo study of the critical dynamics in the $S=\frac{5}{2}$ antiferromagnets ${\mathrm{MnF}}_{2}$ and ${\mathrm{Rb}}_{2}{\mathrm{MnF}}_{4}$ with three-dimensional (3D) and two-dimensional (2D) spin systems, respectively, in zero external field. Both compounds are Heisenberg antiferromagnets with a small uniaxial anisotropy resultin…

[Phys. Rev. B 94, 014424] Published Tue Jul 19, 2016

]]>Lattice defects are inevitably present in two-dimensional materials, with direct implications on their physical and chemical properties. We show that the formation energy of a lattice defect in buckled two-dimensional crystals is not uniquely defined as it takes different values for different bounda…

[Phys. Rev. B 94, 020102(R)] Published Tue Jul 19, 2016

]]>All-optical magnetic switching (AOS) is a recently observed rich and puzzling phenomenon that offers promising technological applications. However, a fundamental understanding of the underlying mechanisms remains elusive. Here we present a model for multishot helicity-dependent AOS in ferromagnetic …

[Phys. Rev. B 94, 020409(R)] Published Tue Jul 19, 2016

]]>The melting curve of sodium for a pressure range up to 100 GPa has been evaluated by the orbital free *ab initio* molecular dynamics method. This method uses the electronic density as the basic variable combined with an approximate electronic kinetic energy functional and a local ionic pseudopotential…

[Phys. Rev. B 94, 024204] Published Tue Jul 19, 2016

]]>To guide improved properties coincident with reduction of critical materials in permanent magnets, we investigate via density functional theory (DFT) the intrinsic magnetic properties of a promising system, $R{\left({\mathrm{Fe}}_{1-x}{\mathrm{Co}}_{x}\right)}_{11}\mathrm{Ti}Z$ with $R=\text{Y}$, Ce and interstitial doping $(Z=\text{H},\text{C},\text{N})$. The magnetization $M$, Curie t…

[Phys. Rev. B 94, 024423] Published Tue Jul 19, 2016

]]>The symmetry of the superconducting order parameter in quasi-two-dimensional bis-ethylenedithio-tetrathiafulvalene (BEDT-TTF) organic superconductors is a subject of ongoing debate. We report *ab initio* density-functional-theory calculations for a number of organic superconductors containing $\kappa $-type l…

[Phys. Rev. B 94, 024515] Published Tue Jul 19, 2016

]]>We obtain the exchange parameter of hybrid functionals by imposing the fundamental condition of a piecewise linear total energy with respect to electron number. For the Perdew-Burke-Ernzerhof (PBE) hybrid family of exchange-correlation functionals (i.e., for an approximate generalized Kohn-Sham theo…

[Phys. Rev. B 94, 035140] Published Tue Jul 19, 2016

]]>We study the impurity scattering effect in black phosphorene (BP) in this work. For a single impurity, we calculate the impurity-induced local density of states (LDOS) in momentum space numerically based on a tight-binding Hamiltonian. In real space, we calculate the LDOS and Friedel oscillation ana…

[Phys. Rev. B 94, 035431] Published Tue Jul 19, 2016

]]>The study of electron transport and scattering processes limiting electron mobility in high-quality semiconductor structures is central to solid-state electronics. Here, we uncover an unavoidable source of electron scattering which is caused by fluctuations of nuclear spins. We calculate the momentu…

[Phys. Rev. B 94, 045309] Published Tue Jul 19, 2016

]]>We study the low temperature conductivity of the electron accumulation layer induced by the very strong electric field at the surface of an ${\text{SrTiO}}_{3}$ sample. Due to the strongly nonlinear lattice dielectric response, the three-dimensional density of electrons $n\left(x\right)$ in such a layer decays with the distan…

[Phys. Rev. B 94, 045310] Published Tue Jul 19, 2016

]]>Electron transport properties of nanoelectronics can be significantly influenced by the inevitable and randomly distributed impurities/defects. For theoretical simulation of disordered nanoscale electronics, one is interested in both the configurationally averaged transport property and its statisti…

[Phys. Rev. B 94, 045424] Published Tue Jul 19, 2016

]]>We calculate the resistance and shot noise in the edge states of a two-dimensional topological insulator that result from the exchange of electrons between these states and conducting puddles in the bulk of the insulator. The two limiting cases where the energy relaxation is either absent or very st…

[Phys. Rev. B 94, 045425] Published Tue Jul 19, 2016

]]>The nickel self-diffusion coefficient was measured in a ${\mathrm{Ni}}_{75}{\mathrm{Si}}_{25}$ alloy in the liquid and undercooled state by quasielastic neutron scattering. The undercooled state was achieved by applying aerodynamic levitation. That containerless technique allowed an undercooling of $\mathrm{\Delta}T\approx 90\phantom{\rule{0.16em}{0ex}}\text{K}$ over 4 h of measurement…

[Phys. Rev. B 94, 014206] Published Mon Jul 18, 2016

]]>Given the unique optical properties of LiF, it is often used as an observation window in high-temperature and -pressure experiments; hence, estimates of its transmission properties are necessary to interpret observations. Since direct measurements of the thermal conductivity of LiF at the appropriat…

[Phys. Rev. B 94, 014309] Published Mon Jul 18, 2016

]]>The quantum excitations of the collective magnetization dynamics in a ferromagnet (F)—magnons—enable spin transport without an associated charge current. This pure spin current can be transferred to electrons in an adjacent nonmagnetic conductor (N). We evaluate the finite temperature noise of the m…

[Phys. Rev. B 94, 014419] Published Mon Jul 18, 2016

]]>Miniaturization of magnon-based devices into the nanometer range would require the utilization of exchange-dominated spin waves of nanometer wavelength. In experiment and theory we show that the intrinsic lifetime and mean free path of the homogeneous acoustic spin wave in ultrathin cobalt films is …

[Phys. Rev. B 94, 014420] Published Mon Jul 18, 2016

]]>We investigate the effect of a unidirectional quenched random field on the anisotropic quantum spin-1/2 $XY$ model, which magnetizes spontaneously in the absence of the random field. We adopt a mean-field approach for this analysis. In general, the models considered have Ising symmetry, and as such th…

[Phys. Rev. B 94, 014421] Published Mon Jul 18, 2016

]]>Quantum phase slips (QPSs) generate voltage fluctuations in superconducting nanowires. Employing the Keldysh technique and making use of the phase-charge duality arguments, we develop a theory of QPS-induced voltage noise in such nanowires. We demonstrate that quantum tunneling of the magnetic flux …

[Phys. Rev. B 94, 014512] Published Mon Jul 18, 2016

]]>We use polarized Raman scattering to study the structural phase transition in ${\mathrm{EuFe}}_{2}{\mathrm{As}}_{2}$, the parent compound of the 122-ferropnictide superconductors. The in-plane lattice anisotropy is characterized by measurements of the side surface with different strains induced by different preparation methods. …

[Phys. Rev. B 94, 014513] Published Mon Jul 18, 2016

]]>We report an antiferromagnetic (AF) ordering at ambient pressure and a superconducting transition under pressure for $\kappa \text{\u2212}{\left(\mathrm{ET}\right)}_{2}\mathrm{C}{\mathrm{F}}_{3}\mathrm{S}{\mathrm{O}}_{3}$ $\mathrm{[}\mathrm{ET}=\mathrm{bis}$(ethylenedithio)tetrathiafulvalene], which has a two-dimensional electronic system with quasi-one-dimensional triangular spin lattice. At ambient pressure, AF ord…

[Phys. Rev. B 94, 020503(R)] Published Mon Jul 18, 2016

]]>The wavelength dependence of the threshold for femtosecond optical breakdown in water provides information on the interplay of multiphoton, tunneling, and avalanche ionization and is of interest for parameter selection in laser surgery. We measured the bubble threshold from ultraviolet to near-infra…

[Phys. Rev. B 94, 024113] Published Mon Jul 18, 2016

]]>The ${\mathrm{V}}_{3}\mathrm{Al}$ alloy with $\mathrm{D}{\mathrm{O}}_{3}$ crystal structure belongs to the family of the very few metallic materials that exhibit a magnetically ordered state with a high ordering temperature (∼600 K) and consist only of nonmagnetic elements. We show that, similarly to the ferromagnetism in the fcc Ni (with ordering …

[Phys. Rev. B 94, 024420] Published Mon Jul 18, 2016

]]>Diamond has been extensively investigated recently due to a wide range of potential applications of nitrogen-vacancy (NV) defect centers existing in a diamond lattice. The applications include magnetometry and quantum information technologies, and long decoherence time $\left({T}_{2}\right)$ of NV centers is critical…

[Phys. Rev. B 94, 024421] Published Mon Jul 18, 2016

]]>We demonstrate that thin polycrystalline films of antiferromagnet CoO, in bilayers with ferromagnetic Permalloy, exhibit slow power-law aging of their magnetization state. The aging characteristics are remarkably similar to those previously observed in thin epitaxial ${\mathrm{Fe}}_{50}{\mathrm{Mn}}_{50}$ films, indicating that …

[Phys. Rev. B 94, 024422] Published Mon Jul 18, 2016

]]>The dynamics of driven pancake vortices in layered superconductors is studied using molecular-dynamics simulations. We found that, with increasing driving force, for strong interlayer coupling, the preexisted vortex lines either directly depin or first transform to two-dimensional (2D) pinned states…

[Phys. Rev. B 94, 024514] Published Mon Jul 18, 2016

]]>The ground-state electronic configurations of the correlated organometallic metallocenes, $M{\mathrm{Cp}}_{2},\phantom{\rule{0.28em}{0ex}}M=\mathrm{V}$, Cr, Mn, Fe, Co, and Ni, are investigated using constraint density functional theory combined with nonempirical ${U}_{\mathrm{eff}}$ parameters determined from linear-response theory. The relative stability of the var…

[Phys. Rev. B 94, 035136] Published Mon Jul 18, 2016

]]>We introduce new three-dimensional (3D) topological phases of two-band models using the Pontryagin-Thom construction. In symmetry class $A$ these are the infinitely many Hopf-Chern topological insulators, which are hybrids of layered Chern insulators and Hopf insulators. Being constructed by a modific…

[Phys. Rev. B 94, 035137] Published Mon Jul 18, 2016

]]>Magnetic impurities deposited on the surface of a thin film experience oscillating-in-space indirect exchange interaction even if the chemical potential is pinned to a middle gap position in the surface electron spectrum, preventing free electrons and holes to exist in the ground state. Oscillating …

[Phys. Rev. B 94, 035138] Published Mon Jul 18, 2016

]]>The significant electron-electron interactions that characterize the $\pi $ electrons of graphene nanoribbons (GNRs) necessitate going beyond one-electron tight-binding description. Existing theories of electron-electron interactions in GNRs take into account one electron–one hole interactions accurately…

[Phys. Rev. B 94, 035139] Published Mon Jul 18, 2016

]]>Exciton, trion, and electron spin dynamics in a 20-nm-wide modulation-doped GaAs single quantum well are investigated using resonant ultrafast two-color Kerr rotation spectroscopy. Excitons and trions are selectively detected by resonant probe pulses while their relative spectral weight is controlle…

[Phys. Rev. B 94, 035303] Published Mon Jul 18, 2016

]]>Using first-principles calculations based on density functional theory, we study the energetics and charge transfer effects in ${\mathrm{MgB}}_{x}$ nanotubes and two-dimensional (2D) sheets. The behavior of adsorbed Mg on 2D boron sheets is found to depend on the amount of electron transfer between the two subsyste…

[Phys. Rev. B 94, 035425] Published Mon Jul 18, 2016

]]>Atomic force microscopy is one of the techniques that allows us to visualize objects that we cannot see directly. The question of what we actually see when we look at an atomic force microscopy image is, however, a subtle one. This paper discusses a scheme that permits the calculation of atomic force microscopy images with relatively little effort. Using electronic density functional theory, the force on the cantilever is calculated as the gradient of the effective potential that governs the electronic structure in density functional theory. In this way, nonclassical contributions to the force can efficiently be taken into account and are translated into an image. Comparison to experimental images shows that the nonclassical contribution to the force can make a visible difference.

[Phys. Rev. B 94, 035426] Published Mon Jul 18, 2016

]]>Emergence of ferromagnetism in nonmagnetic semiconductors is strongly desirable, especially in topological materials because of the possibility of achieving the quantum anomalous Hall effect. Based on first-principles calculations, we propose that for Si thin film grown on metal substrate, the prist…

[Phys. Rev. B 94, 035427] Published Mon Jul 18, 2016

]]>We investigate electron transport through an antidot embedded in a narrow strip of a two-dimensional topological insulator. We focus on the most generic and experimentally relevant case with broken axial spin symmetry. Spin-nonconservation allows additional scattering processes, which change the tra…

[Phys. Rev. B 94, 035428] Published Mon Jul 18, 2016

]]>We study the four-terminal junction of spinless Luttinger liquid wires, which describes either a corner junction of two helical edge states of topological insulators or the tunneling from the spinful wire into the helical edge state. We use the fermionic representation and the scattering state forma…

[Phys. Rev. B 94, 035429] Published Mon Jul 18, 2016

]]>We present Raman spectra of misfit layer $({\mathrm{PbS})}_{1.14}{\mathrm{NbS}}_{2}$ nanotubes and lead intercalated ${\mathrm{NbS}}_{2}$ nanotubes. They represent interesting model systems to investigate the nature of interlayer interaction in layered materials. A direct correlation to the Raman modes of the parent $2H\text{\u2212}{\mathrm{NbS}}_{2}$ compound exists, but…

[Phys. Rev. B 94, 035430] Published Mon Jul 18, 2016

]]>[Phys. Rev. B 94, 039901] Published Mon Jul 18, 2016

]]>The Kitaev model is a toy model for $S$=$\frac{1}{2}$ moments on a honeycomb lattice, which interact via strongly bond-dependent Ising-like interactions. In real material candidates like Na${}_{2}$IrO${}_{3}$, small Heisenberg interactions are also present in addition to dominant Kitaev interactions. The doped Kitaev-Heisenberg model has been predicted to show unconventional superconductivity and spin or charge density wave, and bond-order instabilities. In this paper, the authors have succeeded in surface-doping Na${}_{2}$IrO${}_{3}$ crystals by argon plasma etching and in changing the conductivity by several orders of magnitude. The doped samples show several unusual transport behaviors, including first order spin or charge density wave-like transitions.

[Phys. Rev. B 94, 041109(R)] Published Mon Jul 18, 2016

]]>We investigate the $\mathrm{SU}\left(N\right)$ Hubbard model for the multicomponent fermionic optical lattice system, combining dynamical mean-field theory with the continuous-time quantum Monte Carlo method. We obtain the finite-temperature phase diagrams with $N\le 6$ and find that low-temperature properties depend on the p…

[Phys. Rev. B 94, 041110(R)] Published Mon Jul 18, 2016

]]>Zeeman splitting of one-dimensional hole subbands is investigated in quantum point contacts fabricated on a (311)-oriented GaAs-AlGaAs heterostructure. Transport measurements can determine the magnitude of the $g$ factor, but cannot usually determine the sign. Here we use a combination of tilted field…

[Phys. Rev. B 94, 041406(R)] Published Mon Jul 18, 2016

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