Subsurface charge accumulation imaging of a quantum Hall liquid

TL;DR

This paper introduces a cryogenic scanning-probe technique called subsurface charge accumulation imaging, enabling high-resolution visualization of microscopic electronic structures in two-dimensional electron systems exhibiting the quantum Hall effect.

Contribution

The paper presents a novel subsurface charge accumulation imaging method for directly observing nanometer-scale electronic structures in quantum Hall systems.

Findings

Direct imaging of electronic structures in quantum Hall regime

High-resolution visualization of subsurface charge distributions

Advancement in microscopic probing of 2D electron systems

Abstract

The unusual properties of two-dimensional electron systems that give rise to the quantum Hall effect have prompted the development of new microscopic models for electrical conduction. The bulk properties of the quantum Hall effect have also been studied experimentally using a variety of probes including transport, photoluminescence, magnetization, and capacitance measurements. However, the fact that two-dimensional electron systems typically exist some distance (about 100 nm) beneath the surface of the host semiconductor has presented an important obstacle to more direct measurements of microscopic electronic structure in the quantum Hall regime. Here we introduce a cryogenic scanning-probe technique-- subsurface charge accumulation imaging-- that permits very high resolution examination of systems of mobile electrons inside materials. We use it to image directly the nanometer-scale electronic structures that exist in the quantum Hall regime.