ELECTRONIC-STRUCTURE OF GAAS-ALGAAS HETEROJUNCTIONS IN PARALLEL MAGNETIC-FIELDS

We have performed self-consistent electronic structure calculations for a two-dimensional electron gas confined at a GaAs/AlxGa1-xAs interface in the presence of a parallel magnetic field. Our study has focused on the evolution of the subband states with increasing field strength and the depopulation of higher subbands as a result of diamagnetic energy shifts. Significant differences have been found between the self-consistent results and those obtained by the commonly used perturbative method. These differences can be attributed to two limitations of the perturbative formulation: (i) neglect of the magnetic field dependence of the self-consistent potentials and (ii) neglect of the modification of the density of states from the zero-field behaviour. A comparison of both theoretical formulations with data derived from magnetic depopulation experiments is also made.