Subband-Landau level coupling in a two-dimensional electron gas in tilted magnetic fields

Abstract

The authors report cyclotron resonance measurements on GaInAs-AlInAs heterojunctions in which two electric subbands are occupied in magnetic fields with components both perpendicular and parallel to the interface. The parallel field component increases the energy separation of the two populated subbands and hence shifts the two sets of Landau levels due to the perpendicular field relative to one another. When the two sets of levels are coincident, a splitting is seen in the cyclotron resonance due to coupling of the degenerate states by the parallel magnetic field. The magnitude of the splitting is in agreement with a simple perturbation theory calculation.