Local signatures of electron-electron scattering in an electronic cavity

TL;DR

This study uses scanning gate microscopy to visualize how electron-electron interactions influence conductance in a 2D electronic cavity, revealing energy-dependent signatures of scattering.

Contribution

It demonstrates a method to image electron-electron scattering effects in an electronic cavity using a weakly invasive scanning gate microscopy technique.

Findings

Conductance modulations depend on electron injection energy.

Conductance minima become maxima beyond a specific energy threshold.

Similar microscopic origins to previous invasive tip studies are suggested.

Abstract

We image equilibrium and non-equilibrium transport through a two-dimensional electronic cavity using scanning gate microscopy (SGM). Injecting electrons into the cavity through a quantum point contact close to equilibrium, we raster-scan a weakly invasive tip above the cavity regions and measure the modulated conductance through the cavity. Varying the electron injection energy between $\pm$ 2 meV, we observe that conductance minima turn into maxima beyond the energy threshold of $\pm$ 0.6 meV. This observation bears similarity to previous measurements by Jura et al. [Jura et al., Phys. Rev. B 82, 155328 (2010)] who used a strongly invasive tip potential to study electron injection into an open two-dimensional electron gas. This resemblance suggests a similar microscopic origin based on electron-electron interactions.