Quantum interference in the presence of a metal-to-insulator transition

The negative magnetoresistance related to the quantum interference was studied in the GaAs/AlGaAs doped superlattices as a function of the well thickness and consequently, the disorder induced by the interface roughness. As a result, the disorder driven metal-to-insulator transition was achieved. The qualitatively different magnetoresistances with the positive and negative concavities were observed in the metallic and insulating samples, respectively. Good agreements were found with the theories developed in the limits of the weak and strong disorder. Additionally, a modification of the phase-breaking mechanism was found when crossing from the metallic regime to the insulating one.