Highly anisotropic commensurability oscillations in two-dimensional   holes at the GaAs/AlGaAs (311)A interface
  Measurements of commensurability oscillations in GaAs/AlGaAs two-dimensional (2D) hole systems grown on GaAs (311)A substrates reveal a remarkable anisotropy: the amplitude of the measured commensurability oscillations along the [$\bar{2}$33] direction is about 100 times larger than along [01$\bar{1}$]. For 2D electron systems at similar interfaces, however, we observe nearly isotropic oscillations, suggesting that the anomalous anisotropy is intrinsic to GaAs 2D holes at the (311)A interface. 
Jeng-Bang Yau, Jeng-Ping Lu, Harindran C. Manoharan, and Mansour   Shayegan