Electric-field-induced resonant spin polarization in a two-dimensional electron gas

Electric response of spin polarization in two-dimensional electron gas with structural inversion asymmetry or Rashba spin-orbit coupling subjected to a magnetic field was studied by means of the linear response theory and numerical simulation with the disorder effect. It was found that an electric resonant response of spin polarization occurs when the Fermi surface is located near the crossing of two Landau levels, which is induced from the competition between the spin-orbit coupling and Zeeman splitting. The scaling behavior was investigated with a simplified two-level model, and the height of the resonant peak is reciprocally proportional to the electric field at low temperatures and to temperature for finite electric fields, respectively. Finally, numerical simulation illustrated that impurity potential opens an energy gap near the resonant point and suppresses the effect gradually with increasing strength of disorder. This resonant effect may provide an efficient way to control spin polarization by an external electric field.