Spin dynamics of two-dimensional electrons in a quantum Hall system probed by time-resolved Kerr rotation spectroscopy

Abstract

Time-resolved Kerr rotation spectroscopy under the radio frequency field to depolarize dynamic nuclear polarization reveals the intrinsic spin-relaxation time $({T}_{2}^{\ensuremath{\ast}})$ and $g$ factor of two-dimensional electrons in a quantum Hall system. Out-of-plane magnetic field increases the spin coherence drastically through the Landau level quantization. ${T}_{2}^{\ensuremath{\ast}}$ is enhanced strongly around odd filling factors where a quantum Hall ferromagnet is formed. Collapse of spin coherence and appearance of an anomalous Kerr signal observed around $\ensuremath{\nu}=1$ are discussed in the relation to the formation of Skyrmions.