Imaging the lateral shift of a quantum-point contact using scanning-gate microscopy

TL;DR

This study uses scanning-gate microscopy to visualize and measure the lateral shift of a quantum-point contact in a high-mobility 2DEG, revealing real-space shifts under asymmetric gating.

Contribution

It demonstrates the ability to directly image the lateral shift of a quantum-point contact using scanning-gate microscopy, correlating with transport data and numerical models.

Findings

Observed real-space lateral shifts of the quantum-point contact.

Shift magnitude is consistent with transport measurements.

Scanning-gate microscopy effectively visualizes quantum device behavior.

Abstract

We perform scanning-gate microscopy on a quantum-point contact. It is defined in a high-mobility two-dimensional electron gas of an AlGaAs/GaAs heterostructure, giving rise to a weak disorder potential. The lever arm of the scanning tip is significantly smaller than that of the split gates defining the conducting channel of the quantum-point contact. We are able to observe that the conducting channel is shifted in real space when asymmetric gate voltages are applied. The observed shifts are consistent with transport data and numerical estimations.