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

TL;DR

This paper demonstrates how shifting a quantum wire within a disordered crystal reveals conductance fluctuations in real space, allowing for the counting of individual scatterers through phase-coherent resistance measurements.

Contribution

It introduces a method to observe and count single scatterers in a disordered crystal by spatially displacing a quantum wire and analyzing conductance fluctuations.

Findings

Reproducible conductance fluctuations observed with wire displacement

Fluctuation temperature scale indicates phase coherence

Each fluctuation corresponds to a single scatterer entering or leaving the wire

Abstract

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.