# Finite shot noise and electron heating at quantized conductance in high-mobility quantum point contacts

## TL;DR

This study investigates shot noise in high-mobility quantum point contacts, revealing electron heating effects and their suppression by magnetic fields, with high measurement precision clarifying deviations from theoretical predictions.

## Contribution

It provides the first precise measurement of shot noise in high-mobility QPCs, demonstrating electron heating effects and their magnetic field dependence with 1% accuracy.

## Key findings

- Shot noise slightly exceeds theoretical predictions at zero magnetic field.
- Electron heating near the QPC causes excess noise, reduced by magnetic field.
- Additional noise disappears in the quantum Hall regime.

## Abstract

We report a precise experimental study on the shot noise of a quantum point contact (QPC) fabricated in a GaAs/AlGaAs based high-mobility two-dimensional electron gas (2DEG). The combination of unprecedented cleanliness and very high measurement accuracy has enabled us to discuss the Fano factor to characterize the shot noise with a precision of 1 %. We observed that the shot noise at zero magnetic field exhibits a slight enhancement exceeding the single particle theoretical prediction, and that it gradually decreases as a perpendicular magnetic field is applied. We also confirmed that this additional noise completely vanishes in the quantum Hall regime. These phenomena can be explained by the electron heating effect near the QPC, which is suppressed with increasing magnetic field.