Density-of-states effects in lateral-surface superlattices.

Abstract

We have investigated the transport properties of lateral-surface superlattices fabricated by laser holography on modulation-doped GaAs-${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As field-effect transistors. Peaks in the differential drain-source resistance are observed in a range where the Fermi level has the same order of magnitude as the potential modulation. If a magnetic field is applied perpendicular to the sample, these peaks are shifted while the peak spacing is increased. Using a two-dimensional numerical model, we show that these effects are caused by a modulation density of states in the superlattice potential.