Cyclotron resonance of localized electron systems in the magnetic quantum limit

While the electron-electron interaction does not affect cyclotron resonance according to the Kohn theorem in a perfect lattice of a parabolic semiconductor, it does play a decisive role in disordered systems. We state a general expression for the frequencies of electric-dipole transitions in disordered systems in the presence of strong interactions and magnetic fields. This describes previous cyclotron-resonance experiments in quasi-two-dimensional systems in the magnetic quantum limit and predicts a low-lying disorder-induced mode.