3,037 research outputs found
Quantum interference and electron-electron interactions at strong spin-orbit coupling in disordered systems
Transport and thermodynamic properties of disordered conductors are
considerably modified when the angle through which the electron spin precesses
due to spin-orbit interaction (SOI) during the mean free time becomes
significant. Cooperon and Diffusion equations are solved for the entire range
of strength of SOI. The implications of SOI for the electron-electron
interaction and interference effects in various experimental settings are
discussed.Comment: 4 pages, REVTEX, 1 eps.figure Submitted to Phys. Rev. Let
Phase-Coherent Transport through a Mesoscopic System: A New Probe of Non-Fermi-Liquid Behavior
A novel chiral interferometer is proposed that allows for a direct
measurement of the phase of the transmission coefficient for transport through
a variety of mesoscopic structures in a strong magnetic field. The effects of
electron-electron interaction on this phase is investigated with the use of
finite-size bosonization techniques combined with perturbation theory
resummation. New non-Fermi-liquid phenomena are predicted in the FQHE regime
that may be used to distinguish experimentally between Luttinger and Fermi
liquids.Comment: 4 pages, 3 figures, Revte
A rationale for modeling hydrogen effects on plastic deformation across scales in FCC metals
Although there have been many investigations on the effects of hydrogen on the plastic deformation of metals, an intense debate continues about the physical mechanisms responsible. Most puzzling is the fact that hydrogen appears to be able to both harden and soften FCC metals, depending on the loading conditions. In addition, experiments have shown that hydrogen affects slip system activity differentially, resulting in shear localization of plastic deformation. The work reported in this paper employs a physics-based crystal plasticity model to reproduce the macroscopic response of hydrogen-charged FCC metals through the hydrogen effects on dislocation interactions proposed herein. Different micro-scale mechanisms by which hydrogen may affect plastic deformation are considered, and their resulting macroscopic stress-strain responses under monotonic and cyclic loading are compared. The results support the conclusion that hydrogen screening of dislocations alone cannot explain all the observed macroscopic responses. Instead, it is argued that hydrogen can promote hardening or softening through an increase in glide activation energy and a reduction in dislocation line tension
Orbital mechanism of the circular photogalvanic effect in quantum wells
It is shown that the free-carrier (Drude) absorption of circularly polarized
radiation in quantum well structures leads to an electric current flow. The
photocurrent reverses its direction upon switching the light helicity. A pure
orbital mechanism of such a circular photogalvanic effect is proposed that is
based on interference of different pathways contributing to the light
absorption. Calculation shows that the magnitude of the helicity dependent
photocurrent in -doped quantum well structures corresponds to recent
experimental observations.Comment: 5 pages, 2 figures, to be published in JETP Letter
Spin separation in cyclotron motion
Charged carriers with different spin states are spatially separated in a
two-dimensional hole gas. Due to strong spin-orbit interaction holes at the
Fermi energy have different momenta for two possible spin states travelling in
the same direction and, correspondingly, different cyclotron orbits in a weak
magnetic field. Two point contacts, acting as a monochromatic source of
ballistic holes and a narrow detector in the magnetic focusing geometry are
demonstrated to work as a tunable spin filter.Comment: 4 pages, 2 figure
Universal Equilibrium Currents in the Quantum Hall Fluid
The equilibrium current distribution in a quantum Hall fluid that is
subjected to a slowly varying confining potential is shown to generally consist
of strips or channels of current, which alternate in direction, and which have
universal integrated strengths. A measurement of these currents would yield
direct independent measurements of the proper quasiparticle and quasihole
energies in the fractional quantum Hall states.Comment: 4 pages, Revte
Domain walls and the conductivity of mesoscopic ferromagnets
Quantum interference phenomena in the conductivity of mesoscopic ferromagnets
are considered, particularly with regard to the effects of geometric phases
acquired by electrons propagating through regions of spatially varying
magnetization (due, e.g., to magnetic domain walls). Weak localization and
electron-electron interaction quantum corrections to the conductivity and
universal conductance fluctuations are discussed. Experiments are proposed for
multiply-connected geometries that should reveal conductance oscillations with
variations of the profile of the magnetization.Comment: 4 pages, 1 fugure, RevTEX, Submitted to Phys. Rev. Let
Coulomb "blockade" of Nuclear Spin Relaxation in Quantum Dots
We study the mechanism of nuclear spin relaxation in quantum dots due to the
electron exchange with 2D gas. We show that the nuclear spin relaxation rate is
dramatically affected by the Coulomb blockade and can be controlled by gate
voltage. In the case of strong spin-orbit coupling the relaxation rate is
maximal in the Coulomb blockade valleys whereas for the weak spin-orbit
coupling the maximum of the nuclear spin relaxation rate is near the Coulomb
blockade peaks.Comment: 4 pages, 3 figure
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