Spin-Orbit Coupling Through Inelastic Scattering on Intrasubband Spin Density Excitation

We have studied the spin-orbit coupling via inelastic scattering on the intrasubband spin density excitation. Resonant in elastic scattering was applied to the probe of the anisotropic spin splitting of two dimensional hole systems in p-modulation doped gallium arsenide quantum wells. Intrasubband spin density excitations on a sample was used where evidence of the persistent spin helix was shown by direct spatial mapping. We found approximately equal strengths of Rashba and Dresselhaus spinorbit coupling and anisotropy maximal. The spin splitting for in plane spin was also found maximal and in the perpendicular [110] direction was smaller. The spin splitting of in plane of about 0.18 meV and in the perpendicular in plane direction was found to be smaller than 0.05 meV. We have theoretically studied that only spin flip transitions between the spin orbit split conduction band subbands contributed significantly to the intrasubband spin-density excitation in quasi-backscattering geometry. The obtained results were found in good agreement with previously obtained results.