Effective mass theory of the Rashba effect in heterostructures

Abstract

Within the envelope function scheme, a theory of the Rashba spin-orbit parameter is developed for an arbitrary heterostructure with sharp interfaces. In the first order of perturbation theory, the zero-field spin splitting in a given subband is found to be determined solely by the properties of the wave function at the interfaces; moreover, our results identify the proper electric field responsible for this splitting. The present work gives clear-cut proof that discontinuities in the band-structure parameters in the conduction band are the origin of the Rashba effect. Comparing our results to the Raman scattering data of Jusserand et al. [Phys. Rev. B 51, R4707 (1995)], in its simplest form our present theory rules out the valence-band offset as the source of the Rashba spin splitting, contrary to common belief. The corrections found here give hope for the use of accurate measurements of the Rashba spin splitting in heterostructures as a means to deduce conduction band offsets.