Exchange-enhanced spin splitting in a two-dimensional electron gas in the presence of spin-orbit interaction and magnetic fields

Using a Green's function approach on the basis of the random-phase approximation, we examine how the many-body effect such as exchange interaction affects the spin-splitting in a two-dimensional electron gas system in the presence of the Rashba spin-orbit interaction and Zeeman splitting and of quantizing magnetic fields. We show that such a many-body interaction can lower the energy levels of the system and enlarge the spin-splitting around the Fermi level. We also find that the exchange-enhanced spin-splitting is mainly achieved via intra-Landau level scattering.