Raman Scattering by a Two-Dimensional Fermi Liquid with Spin-Orbit Coupling

We present a microscopic theory of Raman scattering by a two-dimensional Fermi liquid (FL) with Rashba and Dresselhaus types of spin-orbit coupling, and subject to an in-plane magnetic field (B). In the long-wavelength limit, the Raman spectrum probes the collective modes of such a FL: the chiral spin waves. The characteristic features of these modes are a linear-in-q term in the dispersion and the dependence of the mode frequency on the directions of both q and B. All of these features have been observed in recent Raman experiments on CdTe quantum wells.