Landau Transitions and Berry Curvature Effects in Optically Induced Anomalous Hall Current

The anomalous Hall currents (AHC) and spin Hall currents are variants of the Hall effect, with a current flowing perpendicular to an external electrical bias due to the Berry curvature and scattering processes. In this work, we study AHC in bulk GaAs under the formation of Landau levels, which give rise to quantized current responses in the case of two-dimensional GaAs systems. We show that an onset of quantization can also be reached in three-dimensional GaAs systems in the ultrafast (fs to ps) regime. This quantization appears as an enhancement of the AHC for ultrafast excitation of optical transitions between valance and conduction band Landau levels. An analysis of the shape of the resulting THz pulses for different excitation conditions suggests that both, Berry curvature and scattering contribute to the AHC.