Method of determining potential barrier heights at submonolayer AlAs/GaAs heterointerfaces

We report low-field magnetoresistance measurements of a two-dimensional electron gas formed in a GaAs quantum well, in which half a monolayer of AlAs has been inserted into the center of the well. A large anisotropy is observed in both the mobility and the low field magnetoresistance in the orthogonal $\left[1¯10\right]$ and $\left[110\right]$ directions. We describe a method of using the anisotropic low field magnetoresistance to calculate the magnitude of the effective potential of the AlAs submonolayer at the GaAs/AlGaAs heterointerface.