Piezoelectric potential under two-dimensional superlattices

Differential thermal contraction generates stress under gates on the surface of a semiconductor, which in turn induces a potential in a two-dimensional electron gas underneath. We have calculated the deformation and piezoelectric potentials under square and circular gates on common III-V surfaces. The piezoelectric potential is complicated and shows lower symmetry than the gate, which must be taken into account when designing superlattices. The deformation potential does not break the symmetry but is about an order of magnitude smaller. (C) 1998 Published by Elsevier Science B.V. All rights reserved.