# Trapping and counting ballistic non-equilibrium electrons

## TL;DR

This paper demonstrates high-fidelity trapping and counting of ballistic electrons at high energies in GaAs/AlGaAs heterostructures, revealing detailed electron dynamics and scattering probabilities.

## Contribution

It introduces a method for trapping and measuring non-equilibrium electrons with high precision in semiconductor heterostructures.

## Key findings

- Low-loss transport along gate-modified edges
- High-fidelity electron trapping and escape probabilities
- Characterization of electron wave packet distributions

## Abstract

We demonstrate the trapping of electrons propagating ballistically at far-above-equilibrium energies in GaAs/AlGaAs heterostructures in high magnetic field. We find low-loss transport along a gate-modified mesa edge in contrast to an effective decay of excess energy for the loop around a neighboring, mesa-confined node, enabling high-fidelity trapping. Measuring the full counting statistics via single-charge detection yields the trapping (and escape) probabilities of electrons scattered (and excited) within the node. Energetic and arrival-time distributions of captured electron wave packets are characterized by modulating tunnel barrier transmission.