COUPLING BETWEEN ELECTRONS AND ACOUSTIC PHONONS IN SEMICONDUCTOR NANOSTRUCTURES

We show that the coupling between electrons and acoustic phonons in se miconductor confined structures occurs via an interaction, which we ca ll the ''ripple mechanism,'' in addition to the usual deformation pote ntial coupling. Coupling due to the ripple mechanism arises from the p erturbation of the electron wave function by the motion of interfaces. In this work we provide a general derivation of this coupling mechani sm and give detailed expressions for it that are valid for all nanostr ucture systems, including those with quasi-zero-, one-, and two-dimens ional geometries. For the purposes of illustration, calculations of th e electron scattering rates due to acoustic phonons are given here for semiconductor quantum dots in a variety of shapes, including spheres, cubes, and rectangular parallelepipeds. From these results it is foun d that scattering due to the ripple mechanism dominates that from the deformation potential for dot sizes less than similar to 500 Angstrom and that for smaller dot sizes the ripple mechanism contribution can b e much larger than that from the deformation potential.