Tuning of tunneling current noise spectra singularities by localized states charging

TL;DR

This paper presents a theoretical study on how localized impurity states influence tunneling current noise spectra, revealing power-law singularities and peaks due to Coulomb interactions at various bias voltages.

Contribution

It introduces a model explaining the impact of localized states and Coulomb interactions on tunneling noise spectra, highlighting the emergence of singularities and peaks.

Findings

Power law singularity in low-frequency noise spectra.

High-frequency spectral peaks due to Coulomb interactions.

Switching Coulomb interactions alters noise spectrum features.

Abstract

We report the results of theoretical investigations of tunneling current noise spectra in a wide range of applied bias voltage. Localized states of individual impurity atoms play an important role in tunneling current noise formation. It was found that switching "on" and "off" of Coulomb interaction of conduction electrons with two charged localized states results in power law singularity of low-frequency tunneling current noise spectrum ($1/f^{\alpha}$) and also results on high frequency component of tunneling current spectra (singular peaks appear).