arXiv subjects

D. V. Khomitsky

Publications and source records attributed to D. V. Khomitsky.

28 records · Page 2Linked to original sources

arXiv2009

Current-voltage characteristics of tunable ferromagnet-silicon-ferromagnet channels in the spin blockade regime

The steady current-voltage characteristics of ferromagnet-silicon-ferromagnet channels with tunable emitter and collector polarizations are investigated in the presence of spin blockade generalizing the model developed by Pershin Yu V and Di Ventra M (2008 {\it Phys. Rev.} B {\bf 77} 073301). The dependence of the critical current on both collector and emitter polarizations is obtained analytically. It is found that the current amplitude in the channel can be effectively tuned by varying the difference between the collector and emitter ferromagnet polarizations which allows to perform the magnetic manipulation of the electrical current in wide class of both n- and p-doped, low- and high-Ohmic semiconductor channels coupled to ferromagnetic leads.

cond-mat.mes-hall↗

arXiv2009

Electric field-induced spin textures in a superlattice with Rashba and Dresselhaus spin-orbit coupling

The DC charge current, field-induced spin polarization and spin textures are studied in the 1D gated superlattice with both fixed and varying Rashba and Dresselhaus contributions to spin-orbit coupling. It is found that a spin component with zero mean value can demonstrate non-vanishing field-induced spin texture in a superlattice cell which can be probed experimentally, with the highest amplitudes achievable in an interval of comparable Rashba and Dresselhaus terms. The consideration of the finite parameters for collision rate and temperature is found to be non-destructive for the calculated current and spin characteristics depending on all states below the Fermi level.

cond-mat.mes-hall↗

arXiv2009

Model of circular polarization dependence on Mn delta-layer position in LED heterostructures with InGaAs/GaAs quantum well

A simple model of circular polarization dependence on Mn delta-layer position in LED heterostructures with InGaAs/GaAs quantum well is proposed, being able to explain quite accurately recent fascinating experimental results [S.V. Zaitsev, et al., Physica E (2009), doi:10.1016/j.physe.2008.11.003]. The model emphasizes the role of position-dependent exchange interaction between injected holes and Mn spins which significantly affects the hole level splitting in a magnetic field, leading to strong variations of polarization dependence. The role of effective temperature corresponding to the injected hole energy and the broadening caused by the geometrical structure imperfections is also discussed.

cond-mat.mes-hall↗

arXiv2008

Manipulating the spin texture in spin-orbit superlattice by terahertz radiation

The spin texture in a gate-controlled superlattice with Rashba spin-orbit coupling is studied in the presence of external terahertz radiation causing the superlattice miniband transitions. It is shown that the local distribution of spin density can be flipped by tuning the radiation intensity, allowing the controlled coupling of spins and photons with different polarizations.

cond-mat.mes-hall↗

arXiv2007

Scattering on the lateral one-dimensional superlattice with spin-orbit coupling

The problem of scattering of the two-dimensional electron gas on the lateral one-dimensional superlattice both having different strengths of Rashba spin-orbit coupling is investigated. The scattering is considered for all the electron states on a given Fermi level. The distribution of spin density components along the superlattice is studied for the transmitted states where the formation of standing waves is observed. It is found that the shape of spin density distribution is robust against the variations of the Rashba coupling constants, the superlattice potential strength, and the Fermi level in the electron gas.

cond-mat.mes-hall↗

arXiv2006

Spin-orbit lateral superlattices: energy bands and spin polarization in 2DEG

The Bloch spinors, energy spectrum and spin density in energy bands are studied for the two-dimensional electron gas (2DEG) with Rashba spin-orbit (SO) interaction subject to one-dimensional (1D) periodic electrostatic potential of a lateral superlattice. The space symmetry of the Bloch spinors with spin parity is studied. It is shown that the Bloch spinors at fixed quasimomentum describe the standing spin waves with the wavelength equal to the superlattice period. The spin projections in these states have the components both parallel and transverse to the 2DEG plane. The anticrossing of the energy dispersion curves due to the interplay between the SO and periodic terms is observed, leading to the spin flip. The relation between the spin parity and the interband optical selection rules is discussed, and the effect of magnetization of the SO superlattice in the presence of external electric field is predicted.

cond-mat.mes-hall↗

arXiv2005

Statistics of charge transfer in a tunnel junction coupled to an oscillator

The charge transfer statistics of a tunnel junction coupled to a quantum object is studied using the charge projection technique. The joint dynamics of the quantum object and the number of charges transferred through the junction is described by the charge specific density matrix. The method allows evaluating the joint probability distribution of the state of the quantum object and the charge state of the junction.The statistical properties of the junction current are derived from the charge transfer statistics using the master equation for the charge specific density matrix. The theory is applied to a nanoelectromechanical system, and the influence on the average current and the current noise of the junction is obtained for coupling to a harmonic oscillator.

cond-mat.mes-hall↗

arXiv2002

Quantum states and optics in a {\it p}-type heterojunction with lateral surface quantum dot or antidot superlattice subjected to perpendicular magnetic field

The studies of quantum states and optics in a {\it p}-type heterojunction with lateral surface quantum dot (antidot) superlattice and in the presence of perpendicular magnetic field are performed. For the first time the Azbel'-- Hofstadter problem is solved for holes in a complicated valence band described by the $4 \times 4$ Luttinger Hamiltonian. The set of magnetic subbands is obtained for separate hole levels in a wide interval of magnetic field. We found remarkable differences between hole spectra and the Hofstadter "butterfly" for electrons. The influence of the spin-orbit interaction onto wavefunctions and energy spectrum has been investigated. The probabilities of optical transitions between quantum states in the valence band and donors located in the monolayer inside the heterojunction are calculated. The set of parameters (superlattice periods, amplitude of periodic potential, magnitude of magnetic field, etc.) required for experimental observation of splitted hole Landau levels is determined.

cond-mat.mes-hall↗

arXiv2001

Quantum states and magnetooptics in n- and p-type heterojunctions with lateral surface quantum dot (antidot) superlattice subjected to perpendicular magnetic field

The studies of quantum states and optics in n- and p-type heterojunctions with lateral surface quantum dot (antidots) superlattice and in the presence of perpendicular magnetic field are performed. The Azbel' - Hofstadter problem is solved for electrons in conduction band and for holes in valence band described by 4x4 Luttinger Hamiltonian. Under the conditions of non-interactive Landau levels the set of magnetic subbands is obtained for separate electron and hole levels in wide interval of magnetic fields. The influence of spin-orbit interaction onto wavefunctions and energy spectrum in hole magnetic subbands has been investigated. The probabilities of transitions between quantum states in magnetic subbands and monolayer of impurities located inside heterojunction are calculated for two cases: transitions between electron states and acceptors and between hole states and donors. The set of parameters (superlattice periods, amplitude of periodic potential and magntitude of magnetic field, etc.) required for experimental observation of magnetic subbands is found.

cond-mat.mes-hall↗

arXiv1999

Formation of New Fermi Surfaces in 3D Crystals at Ultra High Magnetic Field with Different Orientations

In the tight-binding approximation the Harper like equation describing an electron in 3D crystal subject to a uniform magnetic field is obtained. It is supposed that the vector H can be oriented along several directions in the lattice. The Fermi surfaces relevant to a magnetic flux p/q=1/2 in a simple cubic lattice are built. The quantization rules in magnetic fields slightly distinguished from p/q=1/2 are investigated.

cond-mat.mes-hall↗