Effective potential calculation in a two-dimensional electron gas containing quasi one-dimensional AlAs submonolayer

Abstract

We report low-field magnetoresistance measurements of a two-dimensional electron gas in which half a monolayer of AlAs has been inserted into the centre of the GaAs quantum well. In these devices we observe a low file positive magnetoresistance on GaAs (001) substrates deliberately misoriented by 0.09 degrees toward. the [110] direction in which a critical field causes magnetic breakdown. A large anisotropy is observed in both the mobility and the low field magnetoresistance in the orthogonal [(1) over bar 10] and [110] directions. It is suggested that these effects arise from the quasi periodic effective one-dimensional potentials caused by the insertion of the AlAs submonolayer. We describe a method of using the anisotropic low field magnetoresistance to calculate the magnitude of the effective potential of the AlAs sub-monolayer at the GaAs/AlGaAs heterointerface.