5,044 research outputs found
Photo-excited zero-resistance states in the GaAs/AlGaAs system
The microwave-excited high mobility two-dimensional electron system exhibits,
at liquid helium temperatures, vanishing resistance in the vicinity of , where , m is an
effective mass, e is the charge, and \textit{f} is the microwave frequency.
Here, we summarize some experimental results.Comment: 7 color figures, 5 page
Spin characterization and control over the regime of radiation-induced zero-resistance states
Over the regime of the radiation-induced zero-resistance states and
associated oscillatory magnetoresistance, we propose a low magnetic field
analog of quantum-Hall-limit techniques for the electrical detection of
electron spin- and nuclear magnetic- resonance, dynamical nuclear polarization
via electron spin resonance, and electrical characterization of the nuclear
spin polarization via the Overhauser shift. In addition, beats observed in the
radiation-induced oscillatory-magnetoresistance are developed into a method to
measure and control the zero-field spin splitting due to the Bychkov-Rashba and
bulk inversion asymmetry terms in the high mobility GaAs/AlGaAs system.Comment: IEEE Transactions in Nanotechnology (to be published); 10 pages, 10
color figure
Radiation-induced zero-resistance states with resolved Landau levels
The microwave-photoexcited high mobility GaAs/AlGaAs two-dimensional electron
system exhibits an oscillatory-magnetoresistance with vanishing resistance in
the vicinity of magnetic fields , where , m is an the effective mass, e is the charge,
\textit{f} is the microwave frequency, and =1,2,3... Here, we report
transport with well-resolved Landau levels, and some transmission
characteristics.Comment: 4 pages, 3 color figures, published versio
Temperature effects on microwave-induced resistivity oscillations and zero resistance states in 2D electron systems
In this work we address theoretically a key issue concerning
microwave-induced longitudinal resistivity oscillations and zero resistance
states, as is tempoerature. In order to explain the strong temperature
dependence of the longitudinal resistivity and the thermally activated
transport in 2DEG, we have developed a microscopic model based on the damping
suffered by the microwave-driven electronic orbit dynamics by interactions with
the lattice ions yielding acoustic phonons. Recent experimental results show a
reduction in the amplitude of the longitudinal resistivity oscillations and a
breakdown of zero resistance states as the radiation intensity increases. In
order to explain it we have included in our model the electron heating due to
large microwave intensities and its effect on the longitudinal resistivity.Comment: 4 pages and 4 figures. Accepted in Phys Rev
Observation of a uniform temperature dependence in the electrical resistance across the structural phase transition in thin film vanadium oxide ()
An electrical study of thin films in the vicinity of the structural
phase transition at shows (a) that the electrical resistance
follows over the -range,
covering both sides of the structural transition, and (b) a history dependent
hysteresis loop in upon thermal cycling. These features are attributed here
to transport through a granular network.Comment: 3 pages, 3 color figure
Demonstration of a 1/4 cycle phase shift in the radiation-induced oscillatory-magnetoresistance in GaAs/AlGaAs devices
We examine the phase and the period of the radiation-induced
oscillatory-magnetoresistance in GaAs/AlGaAs devices utilizing in-situ magnetic
field calibration by Electron Spin Resonance of DiPhenyl-Picryl-Hydrazal. The
results confirm a -independent 1/4 cycle phase shift with respect to the condition for , and they also suggest a small
( 2%) reduction in the effective mass ratio, , with respect
to the standard value for GaAs/AlGaAs devices.Comment: 4 pages, 4 color figure
Observation of linear-polarization-sensitivity in the microwave-radiation-induced magnetoresistance oscillations
In the quasi two-dimensional GaAs/AlGaAs system, we investigate the effect of
rotating \textit{in-situ} the electric field of linearly polarized microwaves
relative to the current, on the microwave-radiation-induced magneto-resistance
oscillations. We find that the frequency and the phase of the photo-excited
magneto-resistance oscillations are insensitive to the polarization. On the
other hand, the amplitudes of the magnetoresistance oscillations are remarkably
responsive to the relative orientation between the microwave antenna and the
current-axis in the specimen. The results suggest a striking
linear-polarization-sensitivity in the radiation-induced magnetoresistance
oscillations.Comment: 4 figures, 5 page
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