CYCLOTRON-RESONANCE OF 2-DIMENSIONAL ELECTRON-SYSTEMS UNDER THE INFLUENCE OF IONIZED IMPURITY-SCATTERING

Two-dimensional electron gases in AlGaAs/GaAs heterostructures with well defined additional impurity doping at the interface have been investigated by means of cyclotron resonance. Additional δ-doping in various concentrations within the spread of the wavefunction enabled the investigation of the specific influence of impurities on the CR in the two-dimensional electron gas. Donor (Si)-doped systems exhibit a pronounced, filling factor correlated oscillation of the CR linewidth and of the effective mass. Acceptor (Be)-doped systems exhibit a second resonance over a wide range of magnetic fields and a strong linewidth-narrowing in the quantum limit (ν ≤ 1), when only a single spin Landau level is occupied. The origin of these doping-specific effects is discussed. © 1990.