Current-induced spin polarization in a two-dimensional hole gas

Abstract

We investigate the current-induced spin polarization in the two-dimensional hole gas (2DHG) with the structure inversion asymmetry. By using the perturbation theory, we rederive the effective $k$-cubic Rashba Hamiltonian for 2DHG and the generalized spin operators accordingly. Then based on the linear response theory, we analytically and numerically calculate the current-induced spin polarization with the disorder effect considered. We have found that, quite different from the two-dimensional electron gas, the spin polarization in 2DHG linearly depends on Fermi energy in the low-doping regime, and with increasing Fermi energy, the spin polarization may be suppressed and even changes its sign. We predict a pronounced peak of the spin polarization in 2DHG once the Fermi level is somewhere between the minimum points of two spin-split branches of the lowest light-hole subband. We discuss the possibility of measurements in experiments as regards the temperature and the width of quantum wells.