Suppression of Shot Noise in Quantum Point Contacts in the "0.7" Regime

TL;DR

This paper explains the reduction of shot noise near the 0.7 anomaly in quantum point contacts using a model with a quasi-bound state and two conducting channels, aligning well with experimental data.

Contribution

It introduces a model that accounts for shot noise suppression in the 0.7 regime, incorporating temperature, voltage, and magnetic field effects, and predicts Kondo effect influence.

Findings

Shot noise reduction is explained by the quasi-bound state model.

Calculated shot noise matches experimental observations.

Kondo effect suppresses shot noise dip at low temperature, voltage, and magnetic field.

Abstract

Experimental investigations of current shot noise in quantum point contacts show a reduction of the noise near the 0.7 anomaly. It is demonstrated that such a reduction naturally arises in a model proposed recently to explain the characteristics of the 0.7 anomaly in quantum point contacts in terms of a quasi-bound state, due to the emergence of two conducting channels. We calculate the shot noise as a function of temperature, applied voltage and magnetic field, and demonstrate an excellent agreement with experiments. It is predicted that with decreasing temperature, voltage and magnetic field, the dip in the shot noise is suppressed due to the Kondo effect.