Remote impurity scattering in heterojunctions

Abstract
The commonly used formalism for the ionised remote impurity scattering of electrons in a 2D electron gas contains the following inconsistency. The potential of the donors (e.g. the Si donors in the AlGaAs in the case of a GaAs-AlGaAs heterojunction) is accounted for twice: first in the self-consistent calculation of the envelope function and secondly in the calculation of the scattering rate. Instead, only the scattering as due to the fluctuations in the average field of the donors should be accounted for. The authors have developed expressions for this scattering amplitude and have applied them to a few GaAs-AlGaAs samples with very high mobilities. These samples posed the problem of a serious underestimation of the experimental mobility by the theory. This problem now can be resolved and a better agreement between experiment and theory has been obtained.