We present numerical calculations of the ballistic spin-transport properties quasi-one-dimensional wires in presence spin-orbit (Rashba) interaction. A tight-binding analog Rashba Hamiltonian which models effect is used. By varying robustness coupling and width wire, weak strong regimes are identified. Perfect electron spin-modulation found for former regime, regardless incident Fermi energy mode number. In latter however, spin-conductance has a dependence due to nontrivial subband...

The coupling of geometrical and electronic properties is a promising venue to engineer conduction in graphene. Confinement added strain allows for interplay different transport mechanisms with potential device applications. To investigate signatures on confined geometries, we focus graphene nanoribbons (GNRs) circularly symmetric deformations. In particular, study GNRs an inhomogeneous out-of-plane Gaussian deformation, connected reservoirs. We observe enhancement the density states deformed...

We employ effective-mass theory for degenerate hole bands to calculate the acceptor binding energies Be, Mg, Zn, Ca, C, and Si substitutional acceptors in GaN AlN. The calculations are performed through 6$\ifmmode\times\else\texttimes\fi{}$6 Rashba-Sheka-Pikus Luttinger-Kohn matrix Hamiltonians wurtzite (WZ) zinc-blende (ZB) crystal phases, respectively. An analytic representation pseudopotential is used introduce specific nature of impurity atoms. energy shift due polaron effects also...

We introduce a $p_{z}-d$ coupling model Hamiltonian for the $\pi$-graphene/Au bands that predicts rather large intrinsic spin-orbit (SO) as are being reported in recent experiments and DFT studies. Working within analytical Slater-Koster tight-binding approach we were able to identify overlapping orbitals of relevance enhancement SO both, sublattice symmetric (BC), ATOP (AC) stacking configurations. Our effective reproduces quite well experimental spectrum two registries, addition, its shows...

Transition-metal dichalcogenide heterostructures exhibit moir\'e patterns that spatially modulate the electronic structure across material's plane. For certain material pairs, this modulation acts as a potential landscape with deep, trigonally symmetric wells capable of localizing interlayer excitons, forming periodic arrays quantum emitters. Here, we study these localized exciton states and their optical properties. By numerically solving two-body problem for an interacting electron-hole...

Coherent quantum transport in ferromagnetic/ semiconductor/ ferromagnetic junctions is studied theoretically within the Landauer framework of ballistic transport. We show that coherence can have unexpected implications for spin injection and some intuitive spintronic concepts which are founded semi-classical physics no longer apply: A spin-valve (QSV) effect occurs even absence a net polarized current flowing through device, unlike classical regime. The converse also arises, i.e. zero signal...

We present a derivation of the $6\ifmmode\times\else\texttimes\fi{}6$ valence band Hamiltonian valid for general $[h0\mathrm{il}]$ oriented III-V wurtzite strained substrates. The is performed within exact envelope function theory approach in which $\mathrm{k\ifmmode \hat{}\else \^{}\fi{}}$ operators are written an ordered form when applied to superlattices. choice suitable basis functions $(h0\mathrm{il})$ growth direction, terms those typical (0001) case, allows us define heavy-, light-,...

We present a theory of coherent quantum transport in ferromagnetic/non-magnetic/ferro magnetic heterojunctions. predict coherence to give rise spin valve effect that, unlike its familiar classical analog, occurs even the absence net current through heterostructure. Thus relationship between and charge is qualitatively different presence interference than (semi-)classical regime. This has important implications for design spintronic devices interpretation experiments.

The proximity-induced effects of the nearly commensurate lattice structure a graphene layer AC stacked on Ni(111) and Co(0001) substrates are addressed. To this end, minimal tight-binding Hamiltonian is constructed within Slater-Koster method. We consider hybridizations magnetic $3d$ orbitals Ni (Co) atoms with ${p}_{z}$ graphene, in addition to atomic spin-orbit coupling magnetization atoms. A derivation low-energy perturbed $\ensuremath{\pi}$ bands vicinity Dirac points enables us get...

In recent experiments with ultracold gases a Raman coupling scheme is used to produce both spin-orbit (SO) and Zeeman-type couplings [Y.-J. Lin et al., Nature (London) 471, 83 (2011)]. Their competition drives phase transition magnetized state broken ${Z}_{2}$ symmetry. Using hydrodynamic approach we study confined binary condensate subject SO couplings. We find that in the limit of small healing length unbroken symmetry, boundary magnetization profile has an analytical solution form...

We study the electron scattering produced by local out-of-plane strain deformations in form of Gaussian bumps graphene. Of special interest is taking into account scalar field associated with redistribution charge due to on same footing as pseudomagnetic field. Working Born approximation approach, we show analytically that even when a relatively small considered, strong backscattering and enhancement valley-splitting effect could arise function energy angle incidence. In addition, find...

The spin Hall and longitudinal conductivity of a 2D heavy-hole gas with {\it k}-cubic Rashba Dresselhaus spin-orbit interaction is studied in the ac frequency domain. Using Kubo linear-response theory recently proposed definition for (conserved) current operator suitable spin-3/2 holes, it shown that tensor exhibit very distinguishable features from those obtained standard current. This due to significant contribution spin-torque term arisen alternative which strongly affects magnitude sign...

Using Burt's exact envelope function theory together with symmetry arguments, we have derived an explicit form for the $6\ifmmode\times\else\texttimes\fi{}6$ valence-band effective mass Hamiltonian semiconductor heterojunctions wurtzite ${C}_{6v}^{4}.$ The properly ordered has a similar to that of bulk Hamiltonian, and reduces it when homogeneous system is assumed. parameters are written in terms dimensionless quantities reveal coupling various remote bands ${\ensuremath{\Gamma}}_{1},$...

The Zeeman splitting of the donor spectra in cubic and hexagonal GaN is studied using an effective mass theory approach. Soft-core pseudopotentials were used to describe chemical shift different substitutional dopants. ground states calculated range from 29.5 33.7 meV, with typically 1 meV higher binding phase. Carbon found produce largest energy. ionization levels excited are excellent agreement Hall optical measurements, suggest presence residual C recent experiments.

We study the frequency dependent spin- and charge- conductivity tensors of a two-dimensional electron gas (2DEG) with Rashba Dresselhaus spin-orbit interaction. show that angular anisotropy spin-splitting energy induced by interplay between couplings gives rise to characteristic spectral behavior spin charge response which is significantly different from pure or case. Such new structures open possibility for control optical applying an external bias and/or adjusting light frequency. In...

We show that the tunable hybridization between two lateral quantum dots connected to a nonmagnetic current leads in “hanging-dot” configuration can be used implement bipolar spin filter. The competition Zeeman, exchange interaction, and interdot tunneling (molecular hybridization) yields singlet-triplet transition of double dot ground state allows filtering Coulomb blockade experiments. Its generic nature should make it broadly useful as robust bidirectional polarizer.

Graphene's electronic structure can be fundamentally altered when a substrate- or adatom-induced Kekul\'e superlattice couples the valley and isospin degrees of freedom. Here, we show that band Kekul\'e-textured graphene re-engineered through layer stacking. We predict family bilayers exhibit structures with up to six valleys, room-temperature Dirac quasiparticles whose masses tuned electrostatically. Fermi velocities half as large in pristine put this system strongly coupled regime, where...

We present a theoretical study of the band structure and Landau levels in bilayer graphene at low energies presence transverse magnetic field Rashba spin–orbit interaction regime negligible trigonal distortion. Within an effective low-energy approach (Löwdin partitioning theory), we derive Hamiltonian for that incorporates influence Zeeman effect, and, inclusively, role intrinsic on same footing. Particular attention is paid to energy spectrum levels. Our modeling unveils strong coupling λR...

We report on the theoretical electronic spectra of twisted phosphorene bilayers exhibiting moir\'e patterns, as computed by means a continuous approximation to superlattice Hamiltonian. Our model is constructed interpolating between effective $\mathrm{\ensuremath{\Gamma}}$-point conduction- and valence-band Hamiltonians for different stacking configurations approximately realized across supercell, formulated symmetry grounds. predict realization three distinct regimes electrons holes at...

The joint effects of Kekul\'e lattice distortions and Rashba-type spin-orbit coupling on the electronic properties graphene are explored. We modeled position dependence Rashba energy term in a manner that allows its seamless integration into scheme introduced by Gamayun et al. [New J. Phys. 20, 023016 (2018)] to describe with distortion. Particularly for Kekul\'e-Y (Kek-Y) texture, effective low-energy Dirac Hamiltonian contains new spin-valley locking addition well-known Rashba-induced...

Abstract We present calculations of the frequency‐dependent spin susceptibility tensor a two‐dimensional electron gas with competing Rashba and Dresselhaus spin‐orbit interaction. It is shown that interplay between both types coupling gives rise to an anisotropic spectral behavior density response function which significantly different from vanishing or case. Strong resonances are developed in as consequence angular anisotropy energy spin‐splitting. This characteristic optical modulable may...

Graphene consists in a single-layer carbon crystal where 2p z electrons display linear dispersion relation the vicinity of Fermi level, conveniently described by massless Dirac equation 2+1 spacetime.Spin-orbit effects open gap band structure and offer perspectives for manipulation conducting spin.Ways to manipulate spin-orbit couplings graphene have been generally assessed proximity metals that do not compromise mobility unperturbed system are likely induce strain layer.In this work we...

Graphene deposited on top of a Copper(111) substrate may develop Y-shaped Kekul\'e bond texture (Kekul\'e-Y), locking the momentum its Dirac fermions with valley degree freedom. As consequence, degeneracy band structure is broken, generating an energy dispersion two nested cones different Fermi velocities. In this work, we investigate dynamics electronic wave packets in Kekul\'e-Y superlattice. We show that, as result valley-momentum coupling, valley-driven oscillatory motion ({\it...

We introduce a spin-interference device that comprises quantum ring (QR) with three embedded point contacts (QPCs) and study theoretically its spin transport properties in the presence of Rashba spin-orbit interaction. Two QPCs conform lead-to-ring junctions while third one is placed symmetrically upper arm QR. Using an appropriate scattering model for S-matrix approach, we analyze role on Aharonov-Bohm (AB) Aharonov-Casher (AC) conductance oscillations QR-device. Exact formulas are obtained...