Theory of Quantum Transport in a Two-Dimensional Electron System under Magnetic Fields. IV. Oscillatory Conductivity

The level broadening and the transverse conductivity under magnetic fields of arbitrary strength are studied in the simplest approximation free from the difficulty of divergence caused by the singular nature of the system. Scatterers are assumed to be of short-range. The peak value of the conductivity associated with each Landau level decreases slowly with decreasing magnetic field. Assumption of a phenomenological constant relaxation time is not sufficient and the self-consistency is important even under rather weak magnetic fields. The oscillation of the density of states and the conductivity are numerically calculated.