Driven vibrations of a nanoelectromechanical system based on GaAs/AlGaAs heterostructure containing two-dimensional electron gas are experimentally investigated. The system represents a conductive cantilever with the free end surrounded by a side gate. We show that out-of-plane flexural vibrations of the cantilever are driven when alternating signal biased by a dc voltage is applied to the in-plane side gate. We demonstrate that these vibrations can be on-chip linearly transduced into a low-frequency electrical signal using the heterodyne down-mixing method. The obtained data indicate that the dominant physical mechanism of the vibrations actuation is capacitive interaction between the cantilever and the gate.

The thermopower of a multiprobe ballistic conductor in the form of caterpillarlike Sinai billiard is experimentally investigated. The magnetic-field dependence of both longitudinal thermopower and Nernst-Ettingshausen effect exhibits commensurability oscillations, which are more pronounced than the corresponding oscillations in the magnetoresistance. Results of computer calculations based on the generalized Landauer-Büttiker approach are in agreement with experiment. The observed features in the thermopower originate from drastic difference between the transmission coefficients of quasielectrons ͑above the Fermi level͒ and quasiholes ͑below the Fermi level͒ in the vicinity of geometrical resonances.

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We study electron transport in suspended semiconductor microstructures fabricated from AlAs/GaAs membranes containing a high mobility two-dimensional electron gas. In quantizing magnetic fields, a reflection of edge current channels from the border of suspended area is observed resulting in the absence of vanishing magnetoresistance in the quantum Hall effect (QHE) regime. Relocation of this border out of the Hall bar revives the QHE. We have also found that the critical current of the breakdown of QHE in suspended samples is three times lower than in non-suspended samples due to the peculiarity of heat transport in the membranes.