MAGNETOTRANSPORT IN A WIDE PARABOLIC QUANTUM-WELL

Measurements of the magnetoresistance of a high-quality electron system realized in a selectively doped, parabolic AlxGa1-xAs well are reported. Quantum oscillations in the magnetoresistance are analyzed to obtain the electron densities of the electric subbands. These densities are in agreement with the predictions of a self-consistent calculation of the subband structure for this system. With the magnetic field B slightly tilted away from the sample plane, we observe a dramatic manifestation of the subband-Landau-level coupling. At low B, the magnetic depopulation of the hybrid (electric-magnetic) subbands occurs, while at higher fields, Shubnikov-de Haas-like oscillations (periodic in 1 B) are observed as the Fermi level crosses the quantized energy levels associated with the lowest hybrid subband. © 1990.