Matrix elements for hole-phonon scattering in a semiconductor quantum well

Abstract

Matrix elements for hole-phonon scattering in a quantum well are calculated using a four-band k.p method. The method provides a realistic description of the quantum confined valence states, including the effects of heavy-light hole mixing. This mixing precludes the operation of any symmetry rules for phonon scattering, and the matrix elements are dependent on the specific character of the scattering states involved. For optical phonons, the matrix elements exhibit a strong dependence on the in-plane wavevectors of the scattering states, especially for states lying near the so-called anticrossing regions of the valence subbands. For acoustic (deformation potential) phonons, the matrix elements for intrasubband processes are relatively independent of the in-plane wavevector. In both cases, the larger matrix elements are generally those for intrasubband scattering, with the dominant intersubband processes being those involving adjacent and anticrossing bands.