Scanned Potential Microscopy of Edge States in a Quantum Hall Liquid

TL;DR

This paper employs a low-temperature atomic force microscope to measure local voltage profiles in a quantum Hall system, revealing sharp edge voltage drops that are affected by edge state re-equilibration.

Contribution

It introduces a novel scanning potential microscopy technique to directly observe edge state behavior in quantum Hall liquids.

Findings

Sharp voltage drops at sample edges observed

Re-equilibration suppresses voltage drops

Edge state dynamics are directly visualized

Abstract

Using a low-temperature atomic force microscope as a local voltmeter, we measure the Hall voltage profile in a quantum Hall conductor in the presence of a gate-induced non-equilibrium edge state population at n=3. We observe sharp voltage drops at the sample edges which are suppressed by re-equilibrating the edge states.