Spin density induced by electromagnetic waves in a two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit coupling

We consider the magnetic response of a two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit coupling to a microwave excitation. We generalize the results of Shnirman and Martin [Europhys. Lett. 78, 27001 (2007)], where pure Rashba coupling was studied. We observe that the microwave with the in-plane electric field and the out-of-plane magnetic field creates an out-of-plane spin polarization. The effect is more prominent in clean systems with resolved spin-orbit-split subbands. Considered as response to the microwave magnetic field, the spin-orbit contribution to the magnetization far exceeds the usual Zeeman contribution in the clean limit. The effect vanishes when the Rashba and the Dresselhaus couplings have equal strength.

Figure 1

Real and imaginary parts of the total (orbital plus Zeeman) spin susceptibility $\chi \equiv s_z/B_z$ for $2{\Delta }_F\tau =5$. Solid lines: $W=0.1$, dashed lines: $W=0.5$, dotted lines: $W=0.9$. Parameters assumed as in GaAs: $m_e/m^{\ast }\approx 15$, $g=-0.44$. The results are plotted for $\theta =\pi /4$ which also corresponds to the averaged over $\theta$ susceptibility.

Figure 2

Real and imaginary parts of the total (orbital plus Zeeman) spin susceptibility $\chi \equiv s_z/B_z$ for $2{\Delta }_F\tau =5$ and $W=0.5$. Solid lines: $\theta =0$, dashed lines: $\theta =\pi /2$, dotted lines: $\theta =\pi /4$. Parameters assumed as in GaAs: $m_e/m^{\ast }\approx 15$, $g=-0.44$.