Anisotropic magnetotransport in two-dimensional electron gases on (311)B GaAs substrates

Abstract
Interest in electron transport on high-index GaAs surfaces is increasing, especially since the advent of patterned substrate regrowth, in which high index surfaces are revealed on (001) GaAs after etching. In this paper we observe anisotropic mobility in orthogonal directions in two-dimensional electron gases grown on (311)B GaAs substrates. The mobility in the (233) direction is found to be up to 50 in the (011) direction. The lower mobility is accompanied by a large anomalous negative magnetoresistance. These effects are studied as a function of temperature and carrier density. It is suggested that interface roughness scattering could be a cause for the large anisotropies in mobility and a simple calculation is performed to demonstrate this hypothesis.