HOPPING MAGNETOTRANSPORT IN THE δ-DOPING LAYER

Abstract

We review the observations on hopping transport in planar arrays of Si donor atoms in GaAs epitaxial layers grown by molecular beam epitaxy. It is shown that properly designed δ-doping layers permit one to unambigously identify interference effects that result from the coherent superposition of the tunneling amplitudes along alternative paths in the plane. Magnetic flux through the area generated by the paths destroys the interference and leads to negative magnetoresistance. We discuss the observed non-monotonic variation of the resistance.