Energy-saving spintronics are believed to be implementable on the systems hosting persistent spin helix (PSH) since they support an extraordinarily long lifetime of carriers. However, achieving PSH requires a unidirectional configuration in momentum space, which is practically non-trivial due stringent conditions for fine-tuning Rashba and Dresselhaus spin-orbit couplings. Here, we predict that can intrinsically achieved two-dimensional (2D) group-IV monochalcogenide M X monolayer, new class...

Giant electric polarization of more than 150 µC/cm 2 is predicted for PbVO 3 and BiCoO on the basis first-principles Berry-phase method. The stable crystal structure tetragonally distorted with a large c / ratio significant ionic displacements breaking centrosymmetry. In , key factor that stabilizes such highly realizes an insulating electronic structure, leading to giant polarization, coexistence ferro-orbital antiferro-spin orderings in V 4+ d 1 configuration. It shown same mechanism works...

The zigzag graphene nanoribbon (ZGNR) has an antiferromagnetic property, that is, the relative spin angle theta between two edges is 180 degrees . By using noncollinear first-principles calculations, we find magnetic phase of ZGNR can be controlled by injecting either electrons or holes: as carrier density increases, continuously decreases from to 0 , which indicates net magnetization possible. Either FET doping chemical found

Spin splitting bands that arise in the conduction band minimum (CBM) of ${\text{WS}}_{2}$ monolayer (ML) play an important role spin-orbit phenomena such as spin-valley coupled electronics. However, application strain strongly modifies electronic properties ML, which is expected to significantly affect spin bands. Here, by using fully-relativistic first-principles calculations based on density-functional theory, we show a substantial observed CBM effectively controlled and tuned applying...

We investigated the precise crystal structures and electronic states in a quasi-two-dimensional molecular conductor ${\alpha}$-(BETS)$_2$I$_3$ at ambient pressure. The resistivity of this solid shows metal-to-insulator (MI) crossover $T_{MI}$=50 K. Our x-ray diffraction $^{13}$C nuclear magnetic resonance experiments revealed that maintains inversion symmetry below $T_{MI}$. First-principles calculations found pair anisotropic Dirac cones general k-point, with degenerate contact points Fermi...

The effect of spin-orbit coupling on the electronic properties monolayer (ML) ${\mathrm{PtSe}}_{2}$ is dictated by presence crystal inversion symmetry to exhibit a spin-polarized band without characteristic spin splitting. Through fully relativistic density-functional theory calculations, we show that large splitting can be induced introducing point defects. We calculate stability native defects such as Se vacancy (${\mathrm{V}}_{\text{Se}}$), interstitial (${\mathrm{Se}}_{i}$), Pt...

The established spin splitting in a monolayer (ML) of transition metal dichalcogenides (TMDs) induced by inversion symmetry breaking is dictated mirror operations to exhibit the fully out-of-plane direction polarization. Through first-principles density functional theory calculations, we show that polarity inducing leads sizable having in-plane These splittings are effectively controlled tuning using biaxial strain. Furthermore, admixtures between and spin-polarized states strained polar...

The recent epitaxial growth of the $1T$ phase ${\mathrm{PtSe}}_{2}$ monolayer (ML) has opened possibility for novel applications, in particular a spintronics device. However, contrast to $2H$ transition-metal dichalcogenides (TMDs), absence spin splitting ML may limit functionality application. Through fully relativistic density-functional theory calculations, we show that large can be induced by introducing substitutional halogen impurity. Depending on atomic number $Z$ dopants, observe an...

Large spin splitting at Rashba interface, giving rise to strong spin-momentum locking, is essential for efficient spin-to-charge conversion. Recently, a Cu/Bismuth oxide (Bi2O3) interface has been found exhibit an conversion similar Ag/Bi with large splitting. However, the guiding principle of designing metal/oxide not clarified yet. Here we report non-magnetic (NM) material dependence NM/Bi2O3 interfaces. We employed pumping technique inject current into and evaluated magnitude interfacial...

Motivated by the recent discovery of a large anomalous Nernst effect in Co$_2$MnGa, Fe$_3X$ ($X$=Al, Ga) and Co$_3$Sn$_2$S$_2$, we performed first-principles study to clarify origin enhancement transverse thermoelectric conductivity ($\alpha_{ij}$) these ferromagnets. The intrinsic contribution $\alpha_{ij}$ can be understood terms Berry curvature ($\Omega$) around Fermi level, $\Omega$ is singularly along nodal lines (which are gapless absence spin-orbit coupling) Brillouin zone. We find...

We implemented a finite-difference algorithm for computing anomalous Hall and Nernst conductivity. Based on the expression to evaluate Berry curvature in an insulating system [J. Phys. Soc. Jpn. 74, 1674 (2005)], we extended methods metallic system. calculated conductivity two-dimensional ferromagnetic material ${\mathrm{FeCl}}_{2}$ three-dimensional transition-metals bcc-Fe, hcp-Co, fcc-Ni. Our results are comparable previously reported computed by Kubo formula or Wannier representation. To...

We study, both experimentally and theoretically, temperature electron-density (band-filling) dependence of Seebeck coefficient in B20-type transition-metal monosilicides to critically study the validity Boltzmann transport theory based on band structure as a guiding principle for materials design metallic thermoelectric compounds. The global phase diagram wide range (CrSi–MnSi–FeSi–CoSi–Co 0.85 Ni 0.15 Si their interpolating solid solutions) is obtained. Theoretical results derived from...

The electronic structure, magnetic and electric properties, lattice stability of multiferroic BiMnO3 as a typical system in perovskite Bi transition-metal oxides (BiMO3) are studied from first principles. It is demonstrated theoretically for the time that orbital ordering within Mn eg orbitals actually realized BiMnO3, being consistent with crystallographic data, plays crucial role appearance ferromagnetism. Total-energy calculation shows ferromagnetic state indeed stabilized. Electrical...

Using first-principles calculations, we study the spin–orbit interactions and spin textures of a Bi one-bilayer film, which attracts scientific interest because topological insulator so on. The substrate effect is successfully mimicked by applying on electric field in perpendicular direction breaks inversion symmetry. We highest occupied band around Γ point. Although vortex in-plane component well explained basis conventional Rashba effect, find substantial out-of-plane cannot be model. This...

The persistent spin helix (PSH) that has been widely and exclusively studied in zinc-blende structures is revealed for the first time on surface of a wurtzite structure. Through principles calculations ZnO, quasi-one-dimensional orientation textures identified. Furthermore, wavelength this particular PSH smaller than observed various quantum well structures, thus indicating wurtzite-structured surfaces are suitable spintronics applications.

Finding a new class of materials supporting long spin lifetime is essential in development energy-saving spintronics, which achievable by using persistent helix (PSH) materials. However, for spintronic devices, the PSH states with large splitting required operation at room temperature. By employing first-principles calculations, we show that are achieved SnSe monolayer (ML) functionalized substitutional halogen impurity. We find Fermi level where k-space surface characterized shifted two...

Half-Heusler (HH) alloys are an important and well-studied class of thermoelectric, magnetic, spintronic materials. However, few studies have reported on thermal conductivity magnetic HH alloys. In this study, we performed first-principles calculation the thermoelectric properties a alloy CoMnSb. The lattice CoMnSb was found to be smaller than typical nonmagnetic (CoTiSb, CoZrSb). reason for small group velocity relaxation time acoustic phonons. Moreover, estimated electronic power factor,...

A local-density electronic-band-structure calculation was performed for pyrochlore ruthenium oxides 2 Ru O 7 ( = Bi, Tl and Y). As a general feature, these pyrochlores have band structure composed of antibonding states 4 d t g ) p orbitals near the Fermi energy E F analogous to layered perovskite superconductor Sr RuO . It found that effects ion's are quite important in pyrochlores. Specifically , bands which consist 6 s exist with nearly half-fillings. tight-binding model shows an...

We have performed first-principles calculations for the half-Heusler type ternary compounds M NiSn ( =Ti, Zr, and Hf). To discuss relationship between electronic thermoelectric properties, we evaluate Seebeck coefficients from calculated band structure within Boltzmann transport theory. The temperature carrier concentration dependences of are discussed in terms density states Fermi velocity near edges. all these materials found to be about -300 µV/K at a low n -type room temperature, being...

We investigate the effect of tensile strain on spin splitting at n-type interface LaAlO3/SrTiO3 in terms spin–orbit coupling coefficient α and texture momentum space using first-principles density-functional calculations. Our results show that could be controlled by strain, can enhanced up to 5 times for a 7%, leads persistent helix, which has long lifetime. The is important various applications such as field-effect transistors spin-to-charge conversion.

Fully relativistic first-principles electronic structure calculations based on a noncollinear local spin density approximation (LSDA) are performed for pyrochlore iridates Y$_2$Ir$_2$O$_7$ and Pr$_2$Ir$_2$O$_7$. The all-in, all-out antiferromagnetic (AF) order is stablized by the on-site Coulomb repulsion $U>U_c$ in LSDA+$U$ scheme, with $U_c\sim1.1$~eV 1.3~eV Pr$_2$Ir$_2$O$_7$, respectively. AF semimetals without Weyl points then topologically trivial insulator successively appear further...

The established spin splitting with out-of-plane Zeeman polarizations in the monolayer (ML) of transition metal dichalcogenides (TMDs) is dictated by inversion symmetry breaking together mirror surface plane. Here, density functional theory calculations, we find that polar WSTe ML leads to large exhibiting in-plane Rashba polarizations. We also interplay between Zeeman- and spin-polarized states sensitively affects lifetime, which can be effectively controlled strain. In addition, tunability...