Nonresonant high-frequency excitation of mechanical vibrations in a movable quantum dot

Artikel i vetenskaplig tidskrift, 2015

Nonresonant high-frequency electrostatic actuation of a movable quantum dot (QD) is investigated analytically. The electronic dot state is in tunneling contact with a continuum of electronic states in bulk electrodes. Gate electrodes induce an electric ac-field at the dot. Absorbtion of the field is accompanied by increment or decrement of one vibrational quantum in the QD. It is shown that the rate of increment overcomes the rate of decrement of vibrational quanta when the driving frequency exceeds the inverse tunneling time between the bulk electrodes and the QD. This results in a mechanical instability, leading to relatively large amplitude oscillations of the QD, which are saturated by nonlinear dissipation.