Quantum interference in intentionally disordered doped GaAs/AlxGa1-xAs superlattices -: art. no. 035323

The processes of quantum interference are studied in intentionally disordered doped short-period GaAs/AlxGa1-xAs superlattices where the conductivity can be controlled by the artificial disorder. We found that the usual formula for the weak localization correction to the classical conductivity of superlattices obtained in the propagative Fermi-surface approximation [W. Szott, C. Jedrzejek, and W.P. Kirk, Phys. Rev. Lett. 63, 1980 (1989)] does not allow to one explain the observed negative magnetoresistance. An excelent agreement was obtained between our results and recently published calculations of the quantum interference correction to the conductivity of the strongly disordered superlattices, where the transport regime corresponding to the diffusive Fermi surface was considered [A. Cassam-Chenai and D. Mailly, Phys. Rev. B 52, 1984 (1995)]. We found a tendency toward a propagative regime with an increase of the electron concentration, when the influence of disorder was weakened. The decrease of the dephasing of the electron wave function was observed with an increase of both the doping concentration and the disorder strength. The observed temperature dependence of the dephasing time manifested that the process of the dephasing is modified in the presence of strong disorder.