Anomalous Shubnikov–de Haas oscillations in two-dimensional systems

Abstract

Shubnikov–de Haas (SdH) oscillations have long been used to measure the unequal spin-subband densities of inversion asymmetric two-dimensional (2D) systems. Our experiments and self-consistent numerical calculations for 2D GaAs hole systems indicate that, in general, these oscillations are not simply related to the population of spin-split subbands at zero-magnetic-field. The SdH oscillations depend sensitively on the crystallographic growth directions of a semiconductor quantum well. Our quantum mechanical analysis reveals the inapplicability of conventional Bohr–Sommerfeld quantization for systems with spin–orbit interaction.