p-Type GaAs-(GaAI)As Heterostructures in Tilted Magnetic Fields: Theory and Experiments

Abstract

In a p-type GaAs-(GaAl)As-heterostructure the inversion symmetry is broken giving rise to a complex subband structure. If a strong magnetic field is applied perpendicular to the interface, a complicated set of Landau levels (LLs) arises. The single levels have no longer a well defined spin character and level crossing can occur. This has been confirmed by magnetoresistance experiments [1]. In a magnetic field perpendicular to the interface well resolved Shubnikov-de Haas oscillations can be observed at temperatures below 1K. The complex oscillatory patterns are well explained by the LL calculations performed by Bangert [2]. In order to put the model to a more stringent test, magneto-resistance measurements were performed in which a substantial longitudinal magnetic field was present. For a comparison with theory the previous calculations were extended by incorporating both a parallel and a transverse component of the magnetic field.