5 research outputs found
Transient magnetotransport through a quantum wire
We consider an ideal parabolic quantum wire in a perpendicular magnetic
field. A simple Gaussian shaped scattering potential well or hill is flashed
softly on and off with its maximum at , mimicking a temporary broadening
or narrowing of the wire. By an extension of the Lippmann-Schwinger formalism
to time-dependent scattering potentials we investigate the effects on the
continuous current that is driven through the quantum wire with a vanishingly
small forward bias. The Lippmann-Schwinger approach to the scattering process
enables us to investigate the interplay between geometrical effects and effects
caused by the magnetic field.Comment: RevTeX (pdf-LaTeX), 11 pages with 15 included jpg figure
Time-dependent magnetotransport of a wave packet in a quantum wire with embedded quantum dots
We consider wave packet propagation in a quantum wire with either an embedded
antidot or an embedded parallel double open quantum dot under the influence of
a uniform magnetic field. The magnetoconductance and the time evolution of an
electron wave packet are calculated based on the Lippmann-Schwinger formalism.
This approach allows us to look at arbitrary embedded potential profiles and
illustrate the results by performing computational simulations for the
conductance and the time evolution of the electron wave packet through the
quantum wire. In the double-dot system we observe a long-lived resonance state
that enhances the spatial spreading of the wave packet, and quantum
skipping-like trajectories are induced when the envelop function of the wave
packet covers several subbands in appropriate magnetic fields.Comment: RevTeX, 9 pages with 8 included postscript figure
Rashba spin orbit interaction in a quantum wire superlattice
In this work we study the effects of a longitudinal periodic potential on a
parabolic quantum wire defined in a two-dimensional electron gas with Rashba
spin-orbit interaction. For an infinite wire superlattice we find, by direct
diagonalization, that the energy gaps are shifted away from the usual Bragg
planes due to the Rashba spin-orbit interaction. Interestingly, our results
show that the location of the band gaps in energy can be controlled via the
strength of the Rashba spin-orbit interaction. We have also calculated the
charge conductance through a periodic potential of a finite length via the
non-equilibrium Green's function method combined with the Landauer formalism.
We find dips in the conductance that correspond well to the energy gaps of the
infinite wire superlattice. From the infinite wire energy dispersion, we derive
an equation relating the location of the conductance dips as a function of the
(gate controllable) Fermi energy to the Rashba spin-orbit coupling strength. We
propose that the strength of the Rashba spin-orbit interaction can be extracted
via a charge conductance measurement.Comment: 9 pages, 9 figure