Inter-subband scattering rates in GaAs-GaAlAs heterojunctions

摘要

Magnetoresistance measurements on GaAs-GaAlAs heterojunctions, with two occupied subbands, are presented. With the magnetic field perpendicular to the heterointerface, the difference in energy of the two lowest electric subbands is deduced from the periodicity of Shubnikov-de Haas oscillations. The diamagnetic shift of the energy levels in parallel magnetic fields depopulates the upper subband and, from the difference in resistivity, the inter-subband scattering rate is calculated. This rate is independent of electron density in a given sample and is found to be largely determined by remote impurity scattering.