Tuning Excess Noise by Aharonov-Bohm Interferometry

TL;DR

This paper demonstrates how the excess noise in a mesoscopic Aharonov-Bohm ring can be fully tuned using magnetic flux and electrostatic gating, revealing regions of negative excess noise at finite frequencies.

Contribution

It introduces a method to control and minimize excess noise in a mesoscopic interferometer through magnetic and electrostatic tuning.

Findings

Excess noise is tunable via magnetic flux and gate voltage.

Negative excess noise regions appear at finite frequencies.

Fano factor can be minimized at zero frequency.

Abstract

A voltage bias applied to a conductor induces a change of the current noise with respect to the equilibrium noise known as excess noise. We analyze the excess noise of the electronic current flowing through a mesoscopic Aharonov-Bohm ring threaded by a magnetic flux, coupled to a side gate, and contacted by two metallic electrodes. It is shown that the excess noise can be controlled both magnetically and electrostatically, demonstrating the full tunability of the system. At zero frequency, the ratio of the noise strength to the current (Fano factor) can thereby be minimized. Remarkably, at finite frequency, regions of negative excess noise emerge.