Novel magnetoresistance oscillations in a two-dimensional superlattice potential

Abstract

A new type of magnetoresistance oscillation in a two-dimensional electron gas modulated by a hexagonal lateral periodic electric potential has been observed in GaAs/${\mathrm{Al}}_{\mathit{x}}$${\mathrm{Ga}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As heterostructures. The magnetoresistance oscillations appear at very low magnetic field and the peak positions are directly determined by the magnetic field and the periodicity of the modulation structure. The experimental results can be understood by using a theoretical argument similar to those used in the one-dimensional case. Two kinds of results correlate with structures differing in degree of depletion and the resulting geometry.