Electron spin resonance in a two-dimensional electron gas induced by current or by electric field

Abstract

In asymmetric quantum wells an electric current induces an effective magnetic field acting on conduction electrons due to spin-orbit interaction. A high-frequency electric current can thus induce spin precession. We present and analyze a model for this current-induced (CI) electron spin resonance (ESR). In the low-frequency range, in high-mobility two-dimensional layers, CI ESR is the dominant mechanism of spin excitation. In the high-frequency limit, when the displacement current dominates, the drift current and momentum dissipation become irrelevant. There the CI ESR becomes equivalent to the well-known electric-dipole spin resonance. We show that in both limits the line shape of the power absorption spectra is described by the imaginary component of the dynamic magnetic susceptibility in contrast to experiment, indicative of another so far unknown mechanism.