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Demonstrates room-temperature acoustic charge transport of electrons and holes in an indium gallium arsenide (InGaAs)/gallium arsenide (GaAs) heterostructure. Optical generation of carriers by interband absorption; Separation, storage and transportation of carriers in the piezoelectric potential superlattice of a surface acoustic wave.

Abstract: The transport spectrum of a strongly tunnel-coupled one-electron double quantum dot electrostatically defined in a GaAs/AlGaAs heterostructure is studied. At finite source–drain-voltage we demonstrate the unambiguous identification of the symmetric ground state and the antisymmetric excited state of the double well potential by means of differential conductance measurements. A magnetic field, perpendicular to the two-dimensional electron gas, reduces the extent of the electronic wave-function and thereby decreases the tunnel coupling. This magnetic field also modulates the orbital excitation energies in each individual dot. By additionally tuning the asymmetry of the double well potential we can align the chemical potentials of an excited state of one of the quantum dots and the ground state of the other quantum dot. This results in a second anticrossing with a much larger tunnel splitting than the anticrossing involving the two electronic ground states. [Copyright &y& Elsevier]

We present magnetotransport measurements on freely suspended two-dimensional electron gases. Samples are prepared from GaAs/AlGaAs-heterostructures containing an additional sacrificial layer. The electronic properties of the system are characterized in standard magnetotransport measurements whereas the mechanical degrees of freedom are investigated in radio frequency resonance experiments. The interplay of both can be exploited for ultrasensitive displacement detection. [Copyright &y& Elsevier]