Spin-magnetoplasma waves in a 2D electron system

Oscillations of a 2D electron plasma in a transverse magnetic field have been theoretically studied taking into account spin-orbit interaction. Four branches of spin-plasmon oscillations associated with different selection rules for spin and orbital quantum numbers have been shown to appear at a small plasmon momentum in a semiclassical limit (the Fermi energy is much higher than the Landau quantum). In the quantum case (the filling factor ν is about unity), the number of branches changes from three to six depending on ν value.