Anisotropic scattering potential has been found at the heterointerface of a two-dimensional electron gas in low-temperature transport experiments. This scattering potential has various symmetries depending on the crystalline direction of the interface. The conductivity tensor of a two-dimensional electron gas is theoretically investigated with a Boltzmann equation. Several models of anisotropic elastic scattering potentials are examined. Explicit formulas of the conductivity tensor are given to the lowest order of the potential anisotropy. If isotropic scatterings and anisotropic scatterings coexist, Matthiessen’s rule gives larger mobility than the exact value. The conductivity is isotropic if the number of the symmetry axes of the scattering probability is more than 2.

• Received 4 March 1998

DOI:https://doi.org/10.1103/PhysRevB.58.7151