Inelastic light scattering by the two-dimensional electron gas: Fractional quantum Hall regime and beyond

Mechanisms of resonant inelastic light scattering by the electron gas are evaluated here for their impact in the current research of semiconductor nano-structures. Recent experiments in the fractonal quantum Hall regime highlight the power of the resonant inelastic light-scattering method in studies of electron-electron interactions in semiconductors of reduced dimensions. These applications follow from its capabilities to measure spin-density and charge-density collective modes as well as excitations that are not predicted by conventional response functions of the electron gas. We consider measurements of intersubband excitations of two-dimensional systems in GaAs quantum wells and observations of gap excitations in the fractional quantum Hall effect.