Quantum-interference origin and magnitude of 1/$f$ noise in Dirac nodal line IrO$_2$ nanowires at low temperatures

TL;DR

This study investigates the origin and magnitude of 1/f noise in IrO2 nanowires at low temperatures, linking it to oxygen vacancies and universal conductance fluctuations, with implications for understanding defect-related noise in Dirac nodal line metals.

Contribution

It identifies oxygen vacancies as the source of low-frequency noise in IrO2 nanowires and connects noise behavior to the orbital two-channel Kondo effect.

Findings

Noise magnitude increases at low temperatures.

Oxygen vacancies cause the observed noise.

Number density of defects derived from resistance behavior.

Abstract

We present 1/$f$ noise measurements of IrO$_2$ nanowires from 1.7 to 350 K. Results reveal that the noise magnitude (represented by Hooge parameter $\gamma$) increases at low temperatures, indicating low-frequency resistance noise from universal conductance fluctuations. The cause of this noise is determined to be due to oxygen vacancies in the rutile structure of IrO$_2$. Additionally, the number density of these mobile defects can be calculated from the $\sqrt{T}$ resistance rise caused by the orbital two-channel Kondo effect in the Dirac nodal line metal IrO$_2$.