Shifting a Quantum Wire through a Disordered Crystal: Observation of Conductance Fluctuations in Real Space

T. Heinzel, G. Salis, R. Held, S. Luescher, K. Ensslin, W. Wegscheider, M. Bichler

Published 1999-09-23Version 1

A quantum wire is spatially displaced by suitable electric fields with respect to the scatterers inside a semiconductor crystal. As a function of the wire position, the low-temperature resistance shows reproducible fluctuations. Their characteristic temperature scale is a few hundred millikelvin, indicating a phase-coherent effect. Each fluctuation corresponds to a single scatterer entering or leaving the wire. This way, scattering centers can be counted one by one.