Diffusive magnetotransport in a two-dimensional Rashba system

An analytical approach to calculation of the conductivity tensor, $\sigma$, of a two-dimensional (2D) electron system with Rashba spin-orbit interaction (SOI) in an orthogonal magnetic field is proposed. The electron momentum relaxation is assumed to be due to electron scattering by a random field of short-range impurities, which is taken into account in the Born approximation. An exact expression for the one-particle Green function of an electron with Rashba SOI in an arbitrary magnetic field is suggested. This expression allows us to obtain analytical formulas for the density of states (DOS) and $\sigma$ in the self-consistent Born and ladder approximation, respectively, which hold true in a wide range of magnetic fields, from the weak ($\omega_{c}\tau << 1$) up to the quantizing ($\omega_{c}\tau\gtrsim 1$) ones. It is shown that in the ladder approximation the Rashba SOI has no effect at all on the conductivity magnitude in the whole range of classical (non quantizing) magnetic fields. The Shubnikov-de Haas (SdH) oscillation period is shown to be related to the total charge carrier concentration by the conventional formula, irrespective of the SOI magnitude. A simple equation defining the location of the SdH oscillation beating nodes is obtained. The results are in good agreement with the experimental and recent numerical investigations.