We report on the study of Mn transversal spin relaxation mechanisms in ferromagnetic (Ga,Mn)As. The spins of valence band holes experience exchange interactions with ferromagnetically ordered Mn spins and strong spin relaxation due to spin-orbit coupling. The hole subsystem provides a relaxation cha…

[Phys. Rev. B 92, 245201] Published Tue Dec 01, 2015

]]>We investigate the current debate on the Mn valence in ${\mathrm{Ga}}_{1-x}{\mathrm{Mn}}_{x}\mathrm{N}$, a diluted magnetic semiconductor (DMS) with a potentially high Curie temperature. From a first-principles Wannier-function analysis, we unambiguously find the Mn valence to be close to $2+$ (${d}^{5}$), but in a mixed spin configuration with a…

[Phys. Rev. Lett. 115, 197203] Published Wed Nov 04, 2015

]]>We demonstrate electrical control of ferromagnetism in field-effect transistors with a trilayer quantum well (QW) channel containing an ultrathin *n-type* ferromagnetic semiconductor $(\mathrm{In},\mathrm{Fe})\mathrm{As}$ layer. A gate voltage is applied to control the electron wave functions ${\phi}_{i}$ in the QW, such that the overlap o…

[Phys. Rev. B 92, 161201(R)] Published Thu Oct 01, 2015

]]>We study the effect of Fe impurities in $\mathrm{B}{\mathrm{i}}_{2}\mathrm{S}{\mathrm{e}}_{3}$ on the magnetic phase and topological insulating property using first-principles calculations. In particular, we investigate the ferromagnetic-antiferromagnetic phase transition and the energy gap variation of surface states in Fe-doped $\mathrm{B}{\mathrm{i}}_{2}\mathrm{S}{\mathrm{e}}_{3}$. We find …

[Phys. Rev. B 92, 104405] Published Tue Sep 08, 2015

]]>First-principles calculations to study the electronic and magnetic properties of bulk, oxygen-deficient ${\mathrm{SrTiO}}_{3}$ (STO) under different doping conditions and densities have been conducted. The appearance of magnetism in oxygen-deficient STO is not determined solely by the presence of a single oxygen va…

[Phys. Rev. B 92, 115112] Published Tue Sep 08, 2015

]]>The modulation of the Gilbert damping constant $\alpha $ in (Ga,Mn)As by the application of an electric field is detected by ferromagnetic resonance measurements, where $\alpha $ increases with decreasing hole concentration. The smaller modulation of other magnetic parameters, such as magnetic anisotropy fields and…

[Phys. Rev. Lett. 115, 057204] Published Thu Jul 30, 2015

]]>We report on the topological Hall effect (THE) in centrosymmetric EuO thin films. This THE signal persists down to the lowest temperature in the metallic region below 50 K for the films thinner than 200 nm. The signal rapidly disappears by tilting the applied magnetic field from surface normal, sugg…

[Phys. Rev. B 91, 245115] Published Mon Jun 08, 2015

]]>The strong spin-orbit interaction in the rare-earth elements ensures that even within a ferromagnetic state there is a substantial orbital contribution to the ferromagnetic moment, in contrast to more familiar transition metal systems in which the orbital moment is usually quenched. The orbital-domi…

[Phys. Rev. B 91, 174426] Published Fri May 22, 2015

]]>${}^{57}\mathrm{Fe}$ nuclear forward scattering on the chiral magnet FeGe reveals an extremely large precursor phase region above the helimagnetic ordering temperature ${T}_{C}(p)$ and beyond the pressure-induced quantum phase transition at 19 GPa. The decrease of the magnetic hyperfine field $\u27e8{B}_{\text{hf}}\u27e9$ with pressure is accomp…

[Phys. Rev. Lett. 114, 016803] Published Tue Jan 06, 2015

]]>We report on the spin-lattice interaction and coherent manipulation of electron spins in Mn-doped colloidal PbS quantum dots (QDs) by electron spin resonance. We show that the phase memory time,$\phantom{\rule{0.28em}{0ex}}{T}_{M}$, is limited by Mn–Mn dipolar interactions, hyperfine interactions of the protons (${}^{1}\mathrm{H}$) on the QD capping…

[Phys. Rev. B 90, 205428] Published Fri Nov 21, 2014

]]>We present an experimental study of x-ray absorption near edge structure (XANES) at ${L}_{2,3},\phantom{\rule{0.16em}{0ex}}{M}_{2,3}$, and $K$ edges of, respectively, Fe, Zr, and O in iron-doped zirconia $({\mathrm{ZrO}}_{2}:\mathrm{Fe})$ for different Fe dopant concentrations $x$ (from $x\sim 6\%$ to $x\sim 25\%$ at.) and make the comparison with *ab initio* simulations at the O $K$-…

[Phys. Rev. B 90, 205201] Published Tue Nov 04, 2014

]]>We have investigated the possible evolution of an intrinsic stable ferromagnetic moment in oxygen deficient undoped and magnetically doped ${\mathrm{HfO}}_{2-x}$ thin films grown by reactive molecular beam epitaxy. Neither oxygen vacancies nor substituted Ni in combination with such vacancies results in an observab…

[Phys. Rev. B 90, 134426] Published Thu Oct 30, 2014

]]>Films of Fe-doped ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ that were deliberately fabricated so they contained ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ nanoparticles were deposited on sapphire substrates by pulsed laser deposition at low oxygen pressure. The concentration of Fe was varied between 1% and 5%, and the effect of including 5% of Sn and vacuum annealing wer…

[Phys. Rev. B 90, 144433] Published Tue Oct 28, 2014

]]>We report on the determination of micromagnetic parameters of epilayers of the ferromagnetic semiconductor (Ga,Mn)As, which has an easy axis in the sample plane, and (Ga,Mn)(As,P), which has an easy axis perpendicular to the sample plane. We use an optical analog of ferromagnetic resonance where the…

[Phys. Rev. B 90, 155203] Published Thu Oct 23, 2014

]]>A new diluted ferromagnetic semiconductor $(\mathrm{Sr},\mathrm{Na}){(\mathrm{Zn},\mathrm{Mn})}_{2}{\mathrm{As}}_{2}$ is reported, in which charge and spin doping are decoupled via Sr/Na and Zn/Mn substitutions, respectively, being distinguished from classic $(\mathrm{Ga},\mathrm{Mn})\mathrm{As}$, where charge and spin doping are simultaneously integrated. Different from the recently…

[Phys. Rev. B 90, 155202] Published Tue Oct 14, 2014

]]>A recently discovered magnetic semiconductor ${\mathrm{Ba}}_{1-\mathrm{x}}{\mathrm{K}}_{\mathrm{x}}{\left({\mathrm{Zn}}_{1-\mathrm{y}}{\mathrm{Mn}}_{\mathrm{y}}\right)}_{2}{\mathrm{As}}_{2}$, with its decoupled spin and charge doping, provides a unique opportunity to elucidate the microscopic origin of the magnetic interaction and ordering in dilute magnetic semiconductors (DMSs). We show that (i) the conventional densit…

[Phys. Rev. B 90, 140403(R)] Published Mon Oct 13, 2014

]]>Weyl fermions, which are fermions with definite chiralities, can give rise to anomalous breaking of the symmetry of the physical system that they are a part of. In their $(3+1)$-dimensional realizations in condensed matter systems, i.e., the so-called Weyl semimetals, this anomaly gives rise to topolo…

[Phys. Rev. B 90, 134409] Published Mon Oct 13, 2014

]]>Ferromagnetically doped topological insulators with broken time-reversal symmetry are a prerequisite for observing the quantum anomalous Hall effect. Cr-doped ${(\mathrm{Bi},\mathrm{Sb})}_{2}{(\mathrm{Se},\mathrm{Te})}_{3}$ is the most successful materials system so far, as it combines ferromagnetic ordering with acceptable levels of additional b…

[Phys. Rev. B 90, 134402] Published Fri Oct 03, 2014

]]>The quantum anomalous Hall effect has recently been observed experimentally in thin films of Cr-doped $(\mathrm{Bi},\mathrm{Sb}{)}_{2}{\mathrm{Te}}_{3}$ at a low temperature ($\sim 30\text{\hspace{0.17em}\hspace{0.17em}}\mathrm{mK}$). In this work, we propose realizing the quantum anomalous Hall effect in more conventional diluted magnetic semiconductors with magnetically doped InAs/GaS…

[Phys. Rev. Lett. 113, 147201] Published Mon Sep 29, 2014

]]>Coherent electron-spin dynamics in ${\text{Ga}}_{1-x}{\text{Mn}}_{x}\text{N}$ has been investigated by time-resolved Kerr rotation spectroscopy. The effective electron $g$ factor shows a linear increase with the Mn concentration due to the *s-d* exchange coupling between the conduction electrons and the $d$-shell electrons of ${\mathrm{Mn}}^{3+}$ impuri…

[Phys. Rev. B 90, 125205] Published Mon Sep 29, 2014

]]>We investigate the quantum anomalous Hall effect (QAHE) and related chiral transport in the millimeter-size ${({\mathrm{Cr}}_{0.12}{\mathrm{Bi}}_{0.26}{\mathrm{Sb}}_{0.62})}_{2}{\mathrm{Te}}_{3}$ films. With high sample quality and robust magnetism at low temperatures, the quantized Hall conductance of ${e}^{2}/h$ is found to persist even when the film thickness is be…

[Phys. Rev. Lett. 113, 137201] Published Fri Sep 26, 2014

]]>The transverse voltages generated in a ${\mathrm{Ga}}_{1-x}{\mathrm{Mn}}_{x}\mathrm{As}$ ferromagnetic semiconductor in planar Hall effect and transverse spin Seebeck effect configurations are systematically analyzed. The observed field dependences consist of symmetric and asymmetric contributions. The former is attributed to the planar …

[Phys. Rev. B 90, 104423] Published Wed Sep 24, 2014

]]>Realizing optical control of individual spins in semiconductors is motivated by a promise of using single spins as building blocks for quantum information processing devices. In this work, a group of authors from Grenoble, France study the spin dynamics of an individual Mn atom coupled with a single hole confined in a II-VI semiconductor quantum dot. They demonstrate how the spin of the hole-Mn system can be initialized by optical pumping with circularly polarized light and analyze the sources of the spin relaxation.

[Phys. Rev. B 90, 115307] Published Mon Sep 15, 2014

]]>We report a detailed investigation of the electronic and magnetic properties of the transition metal (TM) doped two-dimensional (2D) ${\mathrm{MoS}}_{2}$ using *ab initio* calculations. The doping is achieved by substituting two or more Mo atoms by TM atoms of the $3d$ series. Additionally, the effect of codoping on th…

[Phys. Rev. B 90, 125304] Published Mon Sep 08, 2014

]]>We report the observation of the fractional quantum Hall effect in the lowest Landau level of a two-dimensional electron system (2DES), residing in the diluted magnetic semiconductor ${\mathrm{Cd}}_{1-x}{\mathrm{Mn}}_{x}\mathrm{Te}$. The presence of magnetic impurities results in a giant Zeeman splitting leading to an unusual ordering of…

[Phys. Rev. B 90, 115302] Published Wed Sep 03, 2014

]]>Surface acoustic waves (SAW) were generated on a thin layer of the ferromagnetic semiconductor (Ga,Mn)(As,P). The out-of-plane uniaxial magnetic anisotropy of this dilute magnetic semiconductor is very sensitive to the strain of the layer, making it an ideal test material for the dynamic control of …

[Phys. Rev. B 90, 094401] Published Tue Sep 02, 2014

]]>The Hall effect in InMnAs layers with MnAs inclusions of 20–50 nm in size is studied both theoretically and experimentally. We find that the anomalous Hall effect can be explained by the Lorentz force caused by the magnetic field of ferromagnetic inclusions and by an inhomogeneous distribution of th…

[Phys. Rev. B 90, 024415] Published Mon Jul 21, 2014

]]>Over the past two decades, the research of (Ga,Mn)As has led to a deeper understanding of relativistic spin-dependent phenomena in magnetic systems. It has also led to discoveries of new effects and demonstrations of unprecedented functionalities of experimental spintronic devices with general appli…

[Rev. Mod. Phys. 86, 855] Published Fri Jul 11, 2014

]]>The relationship between the modern and classical Landau's approach to carrier orbital magnetization is studied theoretically within the envelope function approximation, taking ferromagnetic (Ga,Mn)As as an example. It is shown that while the evaluation of hole magnetization within the modern theory…

[Phys. Rev. B 90, 045202] Published Wed Jul 09, 2014

]]>We carried out a systematic study of magnetic order and magnetic interlayer coupling in Fe/(Ga,Mn)As bilayers using superconducting quantum interference device magnetometry, polarized neutron reflectometry, element-specific x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and x-ray …

[Phys. Rev. B 89, 224409] Published Mon Jun 16, 2014

]]>We theoretically investigate the finite size effect in quantum anomalous Hall (QAH) system. Using Mn-doped HgTe quantum well as an example, we demonstrate that the coupling between the edge states is spin dependent and is related not only to the distance between the edges but also to the doping conc…

[Phys. Rev. B 89, 205431] Published Tue May 27, 2014

]]>We describe a detailed study of the structural, magnetic, and magnetotransport properties of single-crystal, $n$-type, Mn-doped bismuth telluride thin films grown by molecular beam epitaxy. With increasing Mn concentration, the crystal structure changes from the tetradymite structure of the ${\mathrm{Bi}}_{2}{\mathrm{Te}}_{3}$ par…

[Phys. Rev. B 89, 174425] Published Fri May 23, 2014

]]>We show here the existence of the indirect coupling of electron and magnetic or nuclear ion spins in self-assembled quantum dots mediated by electron-electron interactions. With a single localized spin placed in the center of the dot, only the spins of electrons occupying the zero angular momentum s…

[Phys. Rev. B 89, 195308] Published Thu May 22, 2014

]]>(Ga,Mn)As is a paradigm of a diluted magnetic semiconductor which shows ferromagnetism induced by doped hole carriers. With a few controversial models emerging from numerous experimental and theoretical studies, the mechanism of the ferromagnetism in (Ga,Mn)As still remains a puzzling enigma. In thi…

[Phys. Rev. B 89, 205204] Published Mon May 19, 2014

]]>Gadolinium nitride (GdN) nanocontacts were recently experimentally shown to be efficient spin filters. Our study is aimed at identifying and analyzing the physical processes responsible for the high spin polarization of the tunneling current in GdN nanostructures. By the example of planar contacts a…

[Phys. Rev. B 89, 195419] Published Wed May 14, 2014

]]>We predict that C, N, and O dopants in TlBr can display large, localized magnetic moments. Density functional theory based electronic structure calculations show that the moments arise from partial filling of the crystal-field-split localized $p$ states of the dopant atoms. A simple model is introduce…

[Phys. Rev. B 89, 195201] Published Fri May 09, 2014

]]>We have analyzed the magnetic configuration for highly ordered ${\mathrm{Sr}}_{2}$${\mathrm{CrReO}}_{6}$ films as a function of epitaxial strain using magnetometry and x-ray magnetic circular dichroism (XMCD) measurements of Cr, Re, and O sites. The in-plane magnetic moments change significantly when tensile strain is applied. O $K$…

[Phys. Rev. B 89, 180402(R)] Published Thu May 08, 2014

]]>We investigate signatures of electronic correlations in the narrow-gap semiconductor $\mathrm{Fe}{\mathrm{Ga}}_{3}$ by means of electrical resistivity and thermodynamic measurements performed on single crystals of $\mathrm{Fe}{\mathrm{Ga}}_{3}$, ${\mathrm{Fe}}_{1-x}{\mathrm{Mn}}_{x}{\mathrm{Ga}}_{3}$, and $\mathrm{Fe}{\mathrm{Ga}}_{3-y}{\mathrm{Zn}}_{y}$, complemented by a study of the 4$d$ analog material $\mathrm{Ru}{\mathrm{Ga}}_{3}$. We find that the i…

[Phys. Rev. B 89, 195102] Published Tue May 06, 2014

]]>Based on hybrid density-functional calculations, we propose that ferromagnetism in the prototypical bixbyite sesquioxide ${\text{In}}_{2}$${\text{O}}_{3}$ doped with Cr is due to Cr-oxygen vacancy complexes, while isolated Cr cannot support carrier-mediated magnetic coupling. Our proposal is consistent with experimental facts …

[Phys. Rev. B 89, 134423] Published Thu Apr 24, 2014

]]>It has been reported that in a CoFeB$/$MgO$/$CoFeB based tunnel junction, B diffuses into the MgO layer. In this work we consider three possible locations of B in the MgO lattice upon diffusing into the MgO crystal: B substitutes for an Mg site, it substitutes for an O site, or it occupies an interstiti…

[Phys. Rev. B 89, 144412] Published Mon Apr 14, 2014

]]>Combining density functional theory calculations and microscopic tight-binding models, we investigate theoretically the electronic and magnetic properties of individual substitutional transition-metal impurities (Mn and Fe) positioned in the vicinity of the (110) surface of GaAs. For the case of the…

[Phys. Rev. B 89, 165408] Published Tue Apr 08, 2014

]]>The Mn dopant distribution in ultrathin (20 nm) highly doped (nominal $x$ = 0.20) ${Ga}_{1-x}$Mn${}_{x}$As epitaxial films with critical temperatures close to 175 K and magnetization of 100 emu/cm${}^{3}$ is analyzed by Rutherford backscattering spectrometry (RBS) in a random and channeling configuration. We could quantif…

[Phys. Rev. B 89, 115323] Published Mon Mar 31, 2014

]]>This review compiles results of experimental and theoretical studies on thin films and quantum structures of semiconductors with randomly distributed Mn ions, which exhibit spintronic functionalities associated with collective ferromagnetic spin ordering. Properties of $p$-type Mn-containing III-V as …

[Rev. Mod. Phys. 86, 187] Published Mon Mar 24, 2014

]]>Using local-probe magnetic-characterization techniques of muon spin relaxation and electron spin resonance we have investigated the Mn-induced magnetism of the wide-band-gap perovskite SrTiO${}_{3}$. Our results clearly demonstrate that this diluted magnetic oxide remains paramagnetic down to low temperatu…

[Phys. Rev. B 89, 094418] Published Thu Mar 20, 2014

]]>Colloidal Mn${}^{2+}$-doped semiconductor nanocrystals are solution processable analogs of classic phosphor and diluted magnetic semiconductor materials with promising applications ranging from fluorescence microscopy to spintronic information processing. At doping levels of only a few cation mole percent,…

[Phys. Rev. B 89, 115312] Published Wed Mar 19, 2014

]]>The electronic structure of doped Mn in (Ga,Mn)As is studied by resonant inelastic x-ray scattering. From configuration-interaction cluster-model calculations, the line shapes of the Mn ${L}_{3}$ resonant inelastic x-ray scattering spectra can be explained by $d\text{\u2212}d$ excitations from the Mn ground state domina…

[Phys. Rev. Lett. 112, 107203] Published Wed Mar 12, 2014

]]>[Phys. Rev. Lett. 112, 109901] Published Tue Mar 11, 2014

]]>We have synthesized ferromagnetic InMnP, a member of the III-Mn-V ferromagnetic semiconductor family, by Mn ion implantation and pulsed laser annealing. Clear ferromagnetic hysteresis loops and a perpendicular magnetic anisotropy are observed up to a Curie temperature of 42 K. Large values of negati…

[Phys. Rev. B 89, 121301(R)] Published Thu Mar 06, 2014

]]>The authors fabricate strain-free shallow CdTe/(Cd,Mg)Te quantum dots containing isolated Mn atoms. The reduction in strain-induced magnetic anisotropy yields optical and dynamical properties qualitatively different from those of the strained self-assembled dots studied previously.

[Phys. Rev. B 89, 085315] Published Fri Feb 28, 2014

]]>Polarized neutron reflectometry and x-ray reflectometry were used to determine the nanoscale magnetic and chemical depth profiles of the heavy rare-earth nitrides HoN, ErN, and DyN in the form of 15- to 40-nm-thick films. The net ferromagnetic components are much lower than the predictions of densit…

[Phys. Rev. B 89, 064424] Published Wed Feb 26, 2014

]]>We investigate the correlation between spin signals measured in three-terminal (3T) geometry by the Hanle effect and the spin accumulation generated in a semiconductor channel in a lateral (Ga,Mn)As/GaAs Esaki diode device. We systematically compare measurements using a 3T configuration, probing spi…

[Phys. Rev. B 89, 081307(R)] Published Fri Feb 21, 2014

]]>Laser-induced spin dynamics in (In,Mn)As is studied in magnetic fields up to 7 T. It is shown that a laser pulse can effectively excite homogenous spin precession in this compound at the frequency of the ferromagnetic resonance. Laser excitation of this resonance appears to be very ineffective if th…

[Phys. Rev. B 89, 060402(R)] Published Mon Feb 10, 2014

]]>Using first-principles density functional calculations, electronic and optical properties of ferromagnetic semiconductor EuO are investigated. In particular, we have developed a way to obtain the spin-dependent optical response of the magnetic materials, which is helpful to verify the spin-dependent…

[Phys. Rev. B 89, 064404] Published Fri Feb 07, 2014

]]>With angle-resolved photoemission spectroscopy, gap opening is resolved at up to room temperature in the Dirac surface states of molecular beam epitaxy grown Cr-doped ${\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ topological insulator films, which, however, show no long-range ferromagnetic order down to 1.5 K. The gap size is found decre…

[Phys. Rev. Lett. 112, 056801] Published Thu Feb 06, 2014

]]>Resonant *in situ* photoemission from Mn $3d$ states in Ga${}_{1-x}$Mn${}_{x}$As is reported for Mn concentrations down to the very dilute level of 0.1%. Concentration-dependent spectral features are analyzed on the basis of first-principles calculations for systems with selected impurity positions as well as for ran…

[Phys. Rev. B 89, 045312] Published Wed Jan 29, 2014

]]>${\mathrm{Ge}}_{1-x}{\mathrm{Mn}}_{x}\mathrm{Te}$ is shown to be a multiferroic semiconductor, exhibiting both ferromagnetic and ferroelectric properties. By ferromagnetic resonance we demonstrate that both types of order are coupled to each other. As a result, magnetic-field-induced ferroelectric polarization reversal is achieved. Switc…

[Phys. Rev. Lett. 112, 047202] Published Wed Jan 29, 2014

]]>We present a detailed investigation of the magnetic properties in SiC single crystals bombarded with neon ions. Through careful measuring of the magnetization of virgin and irradiated SiC, we decompose the magnetization of SiC into paramagnetic, superparamagnetic, and ferromagnetic contributions. Th…

[Phys. Rev. B 89, 014417] Published Tue Jan 21, 2014

]]>We show experimental evidence of magnetization switching in a single (Ga,Mn)(As,P) semiconducting ferromagnetic layer, attributed to a strong reduction of the magnetization and the anisotropy due to current injection. The nucleation of magnetization reversal is found to occur even in the absence of …

[Phys. Rev. Lett. 112, 026601] Published Tue Jan 14, 2014

]]>Based on first-principles calculations, we demonstrate that Co-decorated silicene can host a quantum anomalous Hall state. The exchange field induced by the Co atoms combined with the strong spin-orbit coupling of the silicene opens a nontrivial band gap at the $K$ point. As compared to other transiti…

[Phys. Rev. B 89, 035409] Published Thu Jan 09, 2014

]]>Magnetic interaction with the gapless surface states in a topological insulator (TI) has been predicted to give rise to a few exotic quantum phenomena. However, the effective magnetic doping of TI is still challenging in the experiment. Using first-principles calculations, the magnetic doping proper…

[Phys. Rev. B 88, 235131] Published Mon Dec 30, 2013

]]>We report the results from magnetic, resistivity, and Hall effect measurements on a ferromagnetically ordered 5% Gd low energy implanted ZnO single crystal. Temperature-dependent magnetization measurements show that the Gd ions do not contribute to the magnetic order; hence, the magnetic order is in…

[Phys. Rev. B 88, 214423] Published Mon Dec 23, 2013

]]>We report on current-induced domain-wall propagation in a patterned GaMnAs microwire with perpendicular magnetization. A slowing down of the propagation velocity has been found when the moving domain wall extends over only half of the width of the wire. This slowing down is related to the elongation…

[Phys. Rev. B 88, 224415] Published Mon Dec 16, 2013

]]>We present experimental and theoretical studies of the magneto-optical properties of $p$-type In${}_{1-x}$Mn${}_{x}$As and In${}_{1-x}$Mn${}_{x}$Sb ferromagnetic semiconductor films in ultrahigh magnetic fields oriented along [001]. Samples were fabricated by molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MO…

[Phys. Rev. B 88, 235204] Published Wed Dec 11, 2013

]]>We report a study of the topological Hall effect (THE) in Fe-doped MnSi and compare it with results from pure MnSi under pressure. We find that Fe doping increases the THE, indicating an enhancement of the magnitude of the emergent gauge field. This is consistent with the concurrent reduction in the…

[Phys. Rev. B 88, 214406] Published Tue Dec 10, 2013

]]>Antiferromagnetic semiconductors are new alternative materials for spintronic applications and spin valves. In this work, we report a detailed investigation of two antiferromagnetic semiconductors $A$MnAs ($A=\mathrm{Li}$, LaO), which are isostructural to the well-known LiFeAs and LaOFeAs superconductors. Here w…

[Phys. Rev. B 88, 184429] Published Wed Nov 27, 2013

]]>In various manganese-based II-VI diluted magnetic semiconductors and their quantum structures, the measured variations of electron spin dephasing time in an external magnetic field are conflicting with the most advanced spin relaxation theory based on quantum kinetic equations. We demonstrate, by ti…

[Phys. Rev. B 88, 201306(R)] Published Wed Nov 27, 2013

]]>A long-standing challenge in spintronics is the development of a stable, processable and tunable organic magnetic semiconductor. We reveal, through first-principles calculations, that a $p$-electron organic molecular magnet, lithium phthalocyanine (LiPc), can display surprisingly strong antiferromagne…

[Phys. Rev. B 88, 180404(R)] Published Tue Nov 26, 2013

]]>We present an investigation of Mn $\delta $-doped layers in Si(001) grown by molecular beam epitaxy. We discovered that a Pb surfactant has significant effect on the structural and magnetic properties of the submonolayer of Mn, which depends on the Si capping layer growth temperature ${T}_{\mathrm{Si}}$, and the Mn coverag…

[Phys. Rev. B 88, 174419] Published Fri Nov 22, 2013

]]>We investigate the effect of an external magnetic field on the physical properties of the acceptor hole states associated with single Mn acceptors placed near the (110) surface of GaAs. Cross-sectional scanning tunneling microscopy images of the acceptor local density of states (LDOS) show that the …

[Phys. Rev. B 88, 205203] Published Tue Nov 12, 2013

]]>We report evidence of a photoinduced coupling between two spins provided by Mn dopants in their neutral acceptor state ${A}^{0}$ in a single $\mathrm{InAs}/\mathrm{GaAs}$ quantum dot. The coupling occurs due to simultaneous exchange interactions between each of the two dopant spins and a photocreated hole. Microphotoluminesce…

[Phys. Rev. Lett. 111, 187401] Published Tue Oct 29, 2013

]]>Electronic and topological properties of silicene adsorbed with 4$d$ transition metal (TM) atoms are investigated by using $ab$ $initio$ methods together with tight-binding models. All six kinds of TM adatoms (Y to Ru) we studied prefer hollow sites of silicene. The interplay of TM-induced exchange intera…

[Phys. Rev. B 88, 165422] Published Wed Oct 23, 2013

]]>The critical magnetic behavior of the colossal magnetocapacitive spinel CdCr${}_{2}$S${}_{4}$ is revisited. Magnetization and susceptibility of single-crystalline samples measured in the temperature range 68–120 K were analyzed by the kink-point method, the modified Arrott plots, the Kouvel-Fisher method, ln $M$ ve…

[Phys. Rev. B 88, 144417] Published Mon Oct 21, 2013

]]>Europium nitride is semiconducting and contains nonmagnetic ${\mathrm{Eu}}^{3+}$, but substoichiometric EuN has Eu in a mix of $2+$ and $3+$ charge states. We show that at ${\mathrm{Eu}}^{2+}$ concentrations near 15%–20% EuN is ferromagnetic with a Curie temperature as high as 120 K. The ${\mathrm{Eu}}^{3+}$ polarization follows that of the ${\mathrm{Eu}}^{2+}$, con…

[Phys. Rev. Lett. 111, 167206] Published Fri Oct 18, 2013

]]>We show ferromagnetic properties of hydrogen-functionalized epitaxial graphene on SiC. Ferromagnetism in such a material is not directly evident as it is inherently composed of only nonmagnetic constituents. Our results nevertheless show strong ferromagnetism with a saturation of $0.9{\mu}_{\mathrm{B}}/\mathrm{\text{hexagon}}$ proje…

[Phys. Rev. Lett. 111, 166101] Published Wed Oct 16, 2013

]]>A quantum kinetic study of correlated spin transfer between optically excited electrons and Mn atoms in a ZnMnSe quantum well is presented. The simulations predict genuine signatures of non-Markovian spin dynamics which are particularly pronounced for special two-color laser excitations with a zero …

[Phys. Rev. B 88, 161302(R)] Published Wed Oct 16, 2013

]]>We report an investigation of long-range ferromagnetic (FM) ordering in Mn-doped MoS${}_{2}$, MoSe${}_{2}$, MoTe${}_{2}$, and WS${}_{2}$ for Mn concentration less than 5$\%$ using density functional theory calculations. The long-range ferromagnetism of Mn spins is mediated by an antiferromagnetic (AFM) exchange between the locali…

[Phys. Rev. B 88, 144409] Published Thu Oct 10, 2013

]]>The quantum anomalous Hall (QAH) effect in magnetic topological insulators is driven by the combination of spontaneous magnetic moments and spin-orbit coupling. Its recent experimental discovery raises the question if higher plateaus can also be realized. Here, we present a general theory for a QAH …

[Phys. Rev. Lett. 111, 136801] Published Tue Sep 24, 2013

]]>We suggest a mechanism causing large positive magnetoresistance (MR) in dilute magnetic semiconductors when hopping via nonmagnetic donor impurities dominates the conductivity. The effect is due to the increase in the characteristic width $\sigma $ of the donor energy distribution with increasing magnetic f…

[Phys. Rev. B 88, 115210] Published Tue Sep 24, 2013

]]>We performed photoinduced inverse spin-Hall effect (ISHE) measurements on Si-doped bulk GaAs at room temperature. The spin current is optically injected in the sample by means of circularly polarized light and is detected through spin-dependent scattering by Si impurities, which provide an electromo…

[Phys. Rev. B 88, 121201(R)] Published Tue Sep 17, 2013

]]>The question of the correlation between magnetization, band splittings, and magnetic circular dichroism (MCD) in the fundamental gap region of dilute magnetic semiconductors is examined experimentally and through model calculations, taking the case of wurtzite Ga${}_{1-x}$Fe${}_{x}$N as an example. Magnetization …

[Phys. Rev. B 88, 115208] Published Tue Sep 17, 2013

]]>Reversibly switching interlayer exchange coupling (IEC) of magnetic semiconductor multilayers between ferromagnetic (FM) and antiferromagnetic (AFM) modes is a difficult but key issue for fabricating semiconductor giant magnetoresistance devices. Here, we show that such tunable IEC is achievable aro…

[Phys. Rev. Lett. 111, 107203] Published Wed Sep 04, 2013

]]>The magnetism in ∼1 at$\%$ Mn-doped nanometric Bi${}_{2}$Se${}_{3}$ epitaxial layers has been studied by ferromagnetic resonance (FMR), magnetometry, and polarized neutron reflectivity (PNR) measurements. The FMR results reveal the formation of an intrinsic homogeneous FM bulk phase, as confirmed by the PNR measurem…

[Phys. Rev. B 88, 075149] Published Fri Aug 30, 2013

]]>Thin films of topological insulator Bi${}_{2}$Se${}_{3}$ were deposited directly on insulating ferromagnetic EuS. Unusual negative magnetoresistance was observed near the zero field below the Curie temperature ${T}_{C}$, resembling the weak localization effect; whereas the usual positive magnetoresistance was recovered …

[Phys. Rev. B 88, 081407(R)] Published Wed Aug 28, 2013

]]>We report high-resolution hard x-ray photoemission spectroscopy results on (Ga,Mn)As films as a function of Mn doping. Supported by theoretical calculations we identify, for both low (1%) and high (13%) Mn doping values, the electronic character of the states near the top of the valence band. Magnet…

[Phys. Rev. Lett. 111, 097201] Published Tue Aug 27, 2013

]]>The effects of Gd doping and O vacancies on the magnetic interaction and Curie temperature ${T}_{C}$ of EuO are studied using first-principles calculations. Linear response calculations in the virtual crystal approximation show a broad maximum in the Curie temperature as a function of doping, which results…

[Phys. Rev. B 88, 054421] Published Mon Aug 26, 2013

]]>We report the discovery of a diluted magnetic semiconductor, Li(Zn,Mn)P, in which charge and spin are introduced independently via lithium off-stoichiometry and the isovalent substitution of Mn${}^{2+}$ for Zn${}^{2+}$, respectively. Isostructural to (Ga,Mn)As, Li(Zn,Mn)P was found to be a $p$-type ferromagnetic se…

[Phys. Rev. B 88, 081203(R)] Published Wed Aug 21, 2013

]]>The quantum Hall effect can only be induced by an out-of-plane magnetic field for two-dimensional electron gases, and similarly, the quantum anomalous Hall effect has also usually been considered for systems with only out-of-plane magnetization. In the present work, we predict that the quantum anoma…

[Phys. Rev. Lett. 111, 086802] Published Tue Aug 20, 2013

]]>The quantum anomalous Hall effect has been predicted in HgMnTe quantum wells with an out-of-plane magnetization of Mn atoms. However, since HgMnTe quantum wells are paramagnetic, an out-of-plane magnetic field is required to polarize magnetic moments of Mn atoms, which inevitably induces Landau leve…

[Phys. Rev. B 88, 085315] Published Mon Aug 19, 2013

]]>The ultrafast light-induced dynamics in an InAs quantum dot doped with a single Mn atom is studied theoretically. Due to the exchange interaction between the Mn atom and the acceptor hole in the quantum dot, an effective two-level system is formed in the ground-state manifold. We show that this two-…

[Phys. Rev. B 88, 085312] Published Mon Aug 19, 2013

]]>We investigate the nonresonant all-optical switching of magnetization. We treat the inverse Faraday effect (IFE) theoretically in terms of the spin-selective optical Stark effect for linearly or circularly polarized light. In the dilute magnetic semiconductors (Ga,Mn)As, strong laser pulses below th…

[Phys. Rev. B 88, 064416] Published Mon Aug 19, 2013

]]>We describe structural, magnetic, and transport properties of the Cd${}_{1-}$${}_{x}$${}_{-y}$Mn${}_{x}$Cr${}_{y}$Te ferromagnetic semiconductor alloy. Bulk Cd${}_{1-x-y}$Mn${}_{x}$Cr${}_{y}$Te crystals containing up to 10$\%$ of Cr ($y$ $=$ 0.10) were grown by the Bridgman method and were found to be strongly $p$ type and ferromagnetic, with the highest Curie te…

[Phys. Rev. B 88, 075205] Published Wed Aug 14, 2013

]]>A series of (Zn,Co)O layers with Co contents $x$ up to 40$\%$ grown by atomic layer deposition have been investigated. All structures deposited at 160${\phantom{\rule{0.16em}{0ex}}}^{\circ}$C show magnetic properties specific to II-VI dilute magnetic semiconductors with localized spins $S=3/2$ coupled by strong but short-range *antiferromagnetic*…

[Phys. Rev. B 88, 085204] Published Mon Aug 12, 2013

]]>Molecular beam epitaxy has been employed to obtain Ga${}_{1-x}$Mn${}_{x}$N films with $x$ up to 10% and Curie temperatures ${T}_{\text{C}}$ up to 13 K. The magnitudes of ${T}_{\text{C}}$ and their dependence on $x$, ${T}_{\text{C}}\left(x\right)\propto {x}^{m}$, where $m=2.2\pm 0.2$, are quantitatively described by a tight-binding model of superexchange interactions and Monte Carlo sim…

[Phys. Rev. B 88, 081201(R)] Published Mon Aug 12, 2013

]]>We employ NMR techniques to investigate the nature of Mn spins in the I-II-V diluted magnetic semiconductor Li(Zn${}_{1-x}$Mn${}_{x}$)P ($x=0.1$, Curie temperature ${T}_{C}=25$ K). We successfully identify the ${}^{7}$Li NMR signals arising from the Li sites adjacent to Mn${}^{2+}$, and probe the static and dynamic properties of Mn spi…

[Phys. Rev. B 88, 041108(R)] Published Wed Jul 31, 2013

]]>The magnetic properties of a ${\mathrm{Co}}_{2}\mathrm{FeAl}/(\mathrm{Ga},\mathrm{Mn})\mathrm{As}$ bilayer epitaxied on GaAs (001) are studied both experimentally and theoretically. Unlike the common antiferromagnetic interfacial interaction existing in most ferromagnet-magnetic semiconductor bilayers, a ferromagnetic interfacial interaction in the ${\mathrm{C\dots}}_{}$

[Phys. Rev. Lett. 111, 027203] Published Tue Jul 09, 2013

]]>We report the synthesis and characterization of a bulk diluted magnetic semiconductor (La${}_{1-x}$Ba${}_{x}$)(Zn${}_{1-x}$Mn${}_{x}$)AsO (0 $\u2a7d$ $x$ $\u2a7d$ 0.2) with a layered crystal structure identical to that of the 1111-type FeAs superconductors. No ferromagnetic order occurs with (Zn,Mn) substitution in the parent compound LaZnAsO…

[Phys. Rev. B 88, 041102(R)] Published Tue Jul 02, 2013

]]>We present a minimal one-dimensional model of collective spin excitations in itinerant ferromagnetic superlattices within the regime of parabolic spin-carrier dispersion. We discuss the cases of weakly and strongly modulated magnetic profiles finding evidence of antiferromagnetic correlations for lo…

[Phys. Rev. Lett. 110, 267205] Published Fri Jun 28, 2013

]]>A modeling approach for standing spin-wave resonances based on a finite-difference formulation of the Landau-Lifshitz-Gilbert equation is presented. In contrast to a previous study [C. Bihler *et al.*, Phys. Rev. B **79**, 045205 (2009)], this formalism accounts for elliptical magnetization precession an…

[Phys. Rev. B 87, 224422] Published Tue Jun 25, 2013

]]>In transition-metal-doped ZnO the energy position of the dopant 3$d$ states relative to the host conduction and valence bands determines the possibility of long-range ferromagnetism. Density functional theory (DFT) can estimate the energy position of the Co-3$d$ states in ZnO:Co but this depends substan…

[Phys. Rev. B 87, 245118] Published Thu Jun 20, 2013

]]>The search for oxide-based room-temperature ferromagnetism has been one of the holy grails in condensed matter physics. Room-temperature ferromagnetism observed in Nb-doped SrTiO${}_{3}$ single crystals is reported in this Rapid Communication. The ferromagnetism can be eliminated by air annealing (making t…

[Phys. Rev. B 87, 220405(R)] Published Tue Jun 18, 2013

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