THE INTERPLAY OF GATE POTENTIAL AND E-E SCATTERING IN SURFACE SUPERLATTICES

Transport measurements were performed on surface superlattices, formed by a,orating gate on a two-dimensional electron gas. We find a suppre ssion of the differential conductance with increasing electric fields, on a scale of a few V cm(-1). Even more remarkable is a strong suppre ssion of conductance with increasing temperature T, where the T-depend ence is quadratic. We attribute these observations to electron-electro n (e-e) scattering which, in the presence of an external modulated pot ential, can have a significant influence on the conductance. We also d iscuss the role of disorder in these systems. (C) 1997 Academic Press Limited