755 research outputs found
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
Bimodal Counting Statistics in Single Electron Tunneling through a Quantum Dot
We explore the full counting statistics of single electron tunneling through
a quantum dot using a quantum point contact as non-invasive high bandwidth
charge detector. The distribution of counted tunneling events is measured as a
function of gate and source-drain-voltage for several consecutive electron
numbers on the quantum dot. For certain configurations we observe
super-Poissonian statistics for bias voltages at which excited states become
accessible. The associated counting distributions interestingly show a bimodal
characteristic. Analyzing the time dependence of the number of electron counts
we relate this to a slow switching between different electron configurations on
the quantum dot
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