Imaging and controlling electron transport inside a quantum ring

TL;DR

This paper demonstrates how scanning probe microscopy can image and control electron transport within a quantum ring, revealing detailed electron behavior and interference effects at the nanoscale.

Contribution

It introduces a method to directly visualize and manipulate electron propagation inside a quantum ring using SPM, advancing nanoscale transport studies.

Findings

Electron propagation inside the quantum ring can be imaged in situ.

Electron transport can be controlled by tuning the SPM tip potential.

The approach reveals coherent and ballistic electron behavior within the device.

Abstract

Traditionally, the understanding of quantum transport, coherent and ballistic1, relies on the measurement of macroscopic properties such as the conductance. While powerful when coupled to statistical theories, this approach cannot provide a detailed image of "how electrons behave down there". Ideally, understanding transport at the nanoscale would require tracking each electron inside the nano-device. Significant progress towards this goal was obtained by combining Scanning Probe Microscopy (SPM) with transport measurements2-7. Some studies even showed signatures of quantum transport in the surrounding of nanostructures4-6. Here, SPM is used to probe electron propagation inside an open quantum ring exhibiting the archetype of electron wave interference phenomena: the Aharonov-Bohm effect8. Conductance maps recorded while scanning the biased tip of a cryogenic atomic force microscope above the quantum ring show that the propagation of electrons, both coherent and ballistic, can be investigated in situ, and even be controlled by tuning the tip potential.