The role of electron interactions in a failed insulator revealed by shot noise

TL;DR

This paper investigates the unusual electrical behavior of failed insulators by measuring shot noise in nitrogen-doped beta-Ta nanojunctions, revealing strong electron interactions and charge hopping as key factors.

Contribution

It demonstrates that electron interactions and charge hopping explain the anomalous resistivity in failed insulators, providing new insights into their electronic properties.

Findings

Shot noise observed in nanojunctions indicates strong electron interactions.

Charge hopping mediated by electron interactions accounts for resistivity behavior.

Results suggest potential applications in spin-orbitronic and superconducting devices.

Abstract

In materials known as failed insulators, electrical resistivity increases as temperature decreases, yet does not diverge - a phenomenon inconsistent with single-particle theories. We investigate the origin of this behavior by measuring shot noise in nanojunctions of nitrogen-doped beta-Ta, a prototypical failed insulator. Junctions as short as 8 nanometers exhibit hot-electron shot noise, indicating strong electron interactions. We show that charge hopping mediated by these interactions explains the anomalous electronic properties. Our findings open new avenues for exploiting electron interactions in spin-orbitronic and superconducting applications of failed insulators.