Transport in two-dimensional Rashba electron systems doped with interacting magnetic impurities

We study the transport properties of two-dimensional electron systems with strong Rashba spin-orbit coupling (SOC) doped with interacting magnetic impurities. Interactions between magnetic impurities cause the formation of magnetic clusters with temperature-dependent mean sizes distributed randomly on the surface of the system. Treating magnetic clusters as scattering centers, by employing a generalized relaxation time approximation we obtain the nonequilibrium distribution functions of Rashba electrons in both regimes of above and below the band-crossing point (BCP) and present the explicit forms of the conductivity in terms of effective relaxation times. We demonstrate that the combined effects of SOC and magnetic clusters cause the system to be anisotropic and the magnetoresistance strongly depends on both the clusters' mean size and spin, the strengths of SOC, and the location of Fermi energy with respect to the BCP. Our results show that there are many contrasts between the transport properties of the system in the two regimes of above and below the BCP. By comparing the anisotropic magnetoresistance (AMR) of the two-dimensional Rashba systems with the surface AMR of three-dimensional magnetic topological insulators, we also point out the differences between these systems.