Spin-orbit Splitting Anisotropy in n-type InGaAs Inversion Layers

Abstract

Using a recently developed spin‐dependent variational theory for the heterojunction electronic structure, we investigate the spin‐orbit (SO) splitting in InGaAs two dimensional electron gases (2DEGs). We discuss in particular its anisotropy, determined by the relative strength of the Rashba and Dresselhaus SO terms. The envelope function formalism is employed analytically, using the 8‐band k⋅p Kane model for the bulk and spin‐dependent variational functions for the Rashba split conduction subbands. The Dresselhaus contribution is included via quasi‐degenerate first order perturbation theory and the total spin‐splitting at the Fermi level is calculated as a function of the Fermi wave‐vector direction and of the 2DEG carrier density. Contrary to what it is usually assumed regarding InGaAs quantum wells, we find significant Dresselhaus contribution and corresponding spin‐orbit anisotropy in the conduction subbands.