MOBILITY ANISOTROPY OF 2-DIMENSIONAL HOLE SYSTEMS IN (311)A GAAS ALXGA1-XAS HETEROJUNCTIONS

We have measured the low-temperature mobility of high-quality two-dimensional hole systems confined at the (311)A GaAs/AlxGa1-xAs interface. Variables were the thickness of the spacer layer separating the carriers from the Si dopants, and the carrier sheet density. A large anisotropy in mobility is found between the [233BAR] and [011BAR] directions. While the high mobility [233BAR] direction yields results analogous to the two-dimensional electron case, we conclude that transport along [011BAR] is almost entirely determined by anisotropic interface roughness scattering.