223 research outputs found
Spin rotation for ballistic electron transmission induced by spin-orbit interaction
We study spin dependent electron transmission through one- and
two-dimensional curved waveguides and quantum dots with account of spin-orbit
interaction. We prove that for a transmission through arbitrary structure there
is no spin polarization provided that electron transmits in isolated energy
subband and only two leads are attached to the structure. In particular there
is no spin polarization in the one-dimensional wire for which spin dependent
solution is found analytically. The solution demonstrates spin evolution as
dependent on a length of wire. Numerical solution for transmission of electrons
through the two-dimensional curved waveguides coincides with the solution for
the one-dimensional wire if the energy of electron is within the first energy
subband. In the vicinity of edges of the energy subbands there are sharp
anomalies of spin flipping.Comment: 9 oages, 7 figure
Unusual spin effect in alkali vapor induced by two orthogonal multiple harmonics of magnetic field
In this paper, we describe the unusual low-frequency magnetic resonances in
alkali vapor with oriented atomic spins regarding the framework of density
matrix formalism. The feature of the resonance is the absence of a constant
component in the external magnetic field. To explain steep increase of the spin
orientation at certain frequencies, we define special closed atomic spin
trajectories governed by periodic magnetic perturbation. Any closed trajectory
is characterized by the frequency of spin motion. The resonance effect was
numerically verified in the paper. For instance, these trajectories can be
observed in an alkali vapor via optical excitation. Surprisingly, the width of
the resonance line is found to be narrower, as one may expect
Electron Correlations in a Quantum Dot with Bychkov-Rashba Coupling
We report on a theoretical approach developed to investigate the influence of
Bychkov-Rashba interaction on a few interacting electrons confined in a quantum
dot. We note that the spin-orbit coupling profoundly influences the energy
spectrum of interacting electrons in a quantum dot. Inter-electron interaction
causes level crossings in the ground state and a jump in magnetization. As the
coupling strength is increased, that jump is shifted to lower magnetic fields.
Low-field magnetization will therefore provide a direct probe of the spin-orbit
coupling strength in a quantum dot
Spin-dependent tunnelling through a symmetric barrier
The problem of electron tunnelling through a symmetric semiconductor barrier
based on zinc-blende-structure material is studied. The Dresselhaus terms
in the effective Hamiltonian of bulk semiconductor of the barrier are shown to
result in a dependence of the tunnelling transmission on the spin orientation.
The difference of the transmission probabilities for opposite spin orientations
can achieve several percents for the reasonable width of the barriers.Comment: 3 pages, Submitted to Phys. Rev.
Two-dimensional electron scattering in regions of nonuniform spin-orbit coupling
We present a theoretical study of elastic spin-dependent electron scattering
caused by a nonuniform Rashba spin-orbit coupling strength. Using the
spin-generalized method of partial waves the scattering amplitude is exactly
derived for the case of a circular shape of scattering region. We found that
the polarization of the scattered waves are strongly anisotropic functions of
the scattering angle. This feature can be utilized to design a good
all-electric spin-polarizer. General properties of the scattering process are
also investigated in the high and low energy limits.Comment: 4 pages, 3 figure
- …