248 research outputs found
Hall-like effect induced by spin-orbit interaction
The effect of spin-orbit interaction on electron transport properties of a
cross-junction structure is studied. It is shown that it results in spin
polarization of left and right outgoing electron waves. Consequently, incoming
electron wave of a proper polarization induces voltage drop perpendicularly to
the direct current flow between source and drain of the considered
four-terminal cross-structure. The resulting Hall-like resistance is estimated
to be of the order of 10^-3 - 10^-2 h/e^2 for technologically available
structures. The effect becomes more pronounced in the vicinity of resonances
where Hall-like resistance changes its sign as function of the Fermi energy.Comment: 4 pages (RevTeX), 4 figures, will appear in Phys. Rev. Let
Observation of Caustics in the Trajectories of Cold Atoms in a Linear Magnetic Potential
We have studied the spatial and temporal dynamics of a cold atom cloud in the
conservative force field of a ferromagnetic guide, after laser cooling has been
switched off suddenly. We observe outgoing 'waves' that correspond to caustics
of individual trajectories of trapped atoms. This provides detailed information
on the magnetic field, the energy distribution and the spin states.Comment: 21 pages, incl. 12 figure
Two-component model of a spin-polarized transport
Effect of the spin-involved interaction of electrons with impurity atoms or
defects to the transport properties of a two-dimensional electron gas is
described by using a simplifying two-component model. Components representing
spin-up and spin-down states are supposed to be coupled at a discrete set of
points within a conduction channel. The used limit of the short-range
interaction allows to solve the relevant scattering problem exactly. By varying
the model parameters different transport regimes of two-terminal devices with
ferromagnetic contacts can be described. In a quasi-ballistic regime the
resulting difference between conductances for the parallel and antiparallel
orientation of the contact magnetization changes its sign as a function of the
length of the conduction channel if appropriate model parameters are chosen.
The effect is in agreement with recent experimental observations.Comment: 4 RevTeX pages with 4 figure
Bound states in the continuum in open Aharonov-Bohm rings
Using formalism of effective Hamiltonian we consider bound states in
continuum (BIC). They are those eigen states of non-hermitian effective
Hamiltonian which have real eigen values. It is shown that BICs are orthogonal
to open channels of the leads, i.e. disconnected from the continuum. As a
result BICs can be superposed to transport solution with arbitrary coefficient
and exist in propagation band. The one-dimensional Aharonov-Bohm rings that are
opened by attaching single-channel leads to them allow exact consideration of
BICs. BICs occur at discrete values of energy and magnetic flux however it's
realization strongly depend on a way to the BIC's point.Comment: 5 pgaes, 4 figure
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