Lifetimes of a two-dimensional electron gas in the presence of spin-orbit interaction

Abstract

Using the momentum-balance equation derived from a Boltzmann equation, we evaluate the quantum and transport lifetimes of a two-dimensional electron gas (2DEG) in the presence of spin-orbit interaction (SOI) induced by the Rashba effect. For low temperatures, the electronic transport lifetimes due to impurity scattering differ significantly between different spin branches. The effect is more pronounced for stronger SOI and/or lower electron density. In contrast, the quantum lifetimes depend very weakly on the strength of the SOI and are in line with experimental findings. These results hold for electron-impurity scattering via screened Coulomb or short-range δ-function potentials. The physical reason behind a small difference of the quantum lifetime in different spin branches is discussed.