Landau-level broadening due to electron-phonon interaction in multiple-quantum-well structures

The theory of Landau-level broadening due to the electron–acoustic-phonon interaction in a quasi-two-dimensional electron gas in multiple-quantum-well structures is investigated. Variations of the Landau-level width with the superlattice period, barrier height, magnetic field, and temperature are studied. Broadening of the Landau levels is sensitive to the quantum-well parameters and is enhanced in the quantized layers. The calculated magnitude of the width of the Landau levels in GaAs/${\mathrm{Al}}_{\mathrm{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathrm{x}}$As for realistic parameters is of the same order of magnitude as that calculated by using electron impurity potentials, thus suggesting the importance of acoustic-phonon scattering at low temperatures.