21 research outputs found
Superlattice Magnetophonon Resonances in Strongly Coupled InAs/GaSb Superlattices
We report an experimental study of miniband magnetoconduction in
semiconducting InAs/GaSb superlattices. For samples with miniband widths below
the longitudinal optical phonon energy we identify a new superlattice
magnetophonon resonance (SLMPR) caused by resonant scattering of electrons
across the mini-Brillouin zone. This new resonant feature arises directly from
the drift velocity characteristics of the superlattice dispersion and total
magnetic quantisation of the superlattice Landau level minibands.Comment: 9 pages, 8 figures, submitted to Phys. Rev.
Effect of electron-electron scattering on magnetointersubband resistance oscillations of two-dimensional electrons in GaAs quantum wells
The low-temperature( K) magnetotransport ( T) of
two-dimensional electrons occupying two subbands (with energy and )
is investigated in GaAs single quantum well with AlAs/GaAs superlattice
barriers. Two series of Shubnikov-de Haas oscillations are found to be
accompanied by magnetointersubband (MIS) oscillations, periodic in the inverse
magnetic field. The period of the MIS oscillations obeys condition
, where is the
subband energy separation, is the cyclotron frequency, and is
the positive integer. At =4.2 K the oscillations manifest themselves up to
=100. Strong temperature suppression of the magnetointersubband oscillations
is observed. We show that the suppression is a result of electron-electron
scattering. Our results are in good agreement with recent experiments,
indicating that the sensitivity to electron-electron interaction is the
fundamental property of magnetoresistance oscillations, originating from the
second-order Dingle factor.Comment: 6 pages, 4 figure
Inter-subband resistance oscillations in crossed electric and magnetic fields
Quantum oscillations of nonlinear resistance are investigated in response to
electric current and magnetic field applied perpendicular to single GaAs
quantum wells with two populated subbands. At small magnetic fields
current-induced oscillations appear as Landau-Zener transitions between Landau
levels inside the lowest subband. Period of these oscillations is proportional
to the magnetic field. At high magnetic fields different kind of quantum
oscillations emerges with a period,which is independent of the magnetic field.
At a fixed current the oscillations are periodic in inverse magnetic field with
a period that is independent of the dc bias. The proposed model considers these
oscillations as a result of spatial variations of the energy separation between
two subbands induced by the electric current.Comment: 9 Pages, 10 Figure
Longitudinal spin transport in diluted magnetic semiconductor superlattices: the effect of the giant Zeeman splitting
Longitudinal spin transport in diluted magnetic semiconductor superlattices
is investigated theoretically. The longitudinal magnetoconductivity (MC) in
such systems exhibits an oscillating behavior as function of an external
magnetic field. In the weak magnetic field region the giant Zeeman splitting
plays a dominant role which leads to a large negative magnetoconductivity. In
the strong magnetic field region the MC exhibits deep dips with increasing
magnetic field. The oscillating behavior is attributed to the interplay between
the discrete Landau levels and the Fermi surface. The decrease of the MC at low
magnetic field is caused by the exchange interaction between the electron
in the conduction band and the magnetic ions.Comment: 6 pages, 9 figures, submitted to Phys. Rev.