Anomalies in the cyclotron resonance of quasi-two-dimensional electrons in silicon at low electron densities

Systematic line-shape studies of the anomalous cyclotron resonance of quasi-two-dimensional electrons in Si metal-oxide-semiconductor devices at low temperature and low densities have revealed a multiple-line structure. The ratio of electron density to magnetic field (Landau-level filling factor) at which the anomalies appear is systematically correlated with the inverse of the electron peak effective mobility, demonstrating the importance of localization. Several features cannot be explained by single-particle localization, and it is argued that electron-electron correlations also play an importnat role.