Electric-Field Induced Spin Excitation in Quantum Wells with Rashba–Dresselhaus Spin-Orbit Coupling

The spin-rotation symmetry in spin-orbit coupled two-dimensional electron systems gives rise to a long-lived spin excitation that is robust against short-range impurity scattering. The influence of a constant in-plane electric field on this persistent spin helix is studied. To probe field-mediated spin modes, a surface acoustic wave is exploited that provides the wave-vector for resonant excitation. The approach takes advantage of methods worked out in the field of space-charge waves. A sharp resonance in the electric field dependence of the magnetization is identified.