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

We have performed self-consistent electronic structure calculations fo r a two-dimensional electron gas confined at a GaAs/AlxGa1-xAs interfa ce 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 en ergy shifts. Significant differences have been found between the self- consistent results and those obtained by the commonly used perturbativ e method. These differences can be attributed to two limitations of th e perturbative formulation: (i) neglect of the magnetic field dependen ce of the self-consistent potentials and (ii) neglect of the modificat ion of the density of states from the zero-field behaviour. A comparis on of both theoretical formulations with data derived from magnetic de population experiments is also made.