Acoustic switching of quantum states in semiconductors

Abstract

The interaction between solitary elastic strain pulses (acoustic solitons) and localized holes in low-dimensional silicon structures is studied theoretically. It is shown that a soliton propagating through a region of hole localization converts it from one quantum state to another characterized by a different projection of the angular momentum. This effect originates in splitting of the ground hole state, which is degenerate in the absence of a perturbation, by the elastic strain. A detailed microscopic calculation of the acoustic switching of quantum mechanical states is carried out for holes localized at a quantum dot or at a shallow impurity acceptor in a quantum well. It is shown that the acoustic soliton amplitude required for complete reversal of the projected angular momentum of a hole corresponds to the amplitude of typical experimentally produced strain pulses.