Stability of Metal Nanowires at Ultrahigh Current Densities

TL;DR

This paper presents a theoretical framework for analyzing the stability of metal nanowires under ultrahigh current densities, revealing conditions for stability and the existence of bias-dependent stable geometries.

Contribution

It introduces a generalized grand canonical potential incorporating nonequilibrium electron distributions and Coulomb interactions, enabling stability analysis of nanowires at extreme currents.

Findings

Nanowires can sustain current densities up to 10^11 A/cm^2.

Certain conductance values confer enhanced stability under high current.

Reentrant stability zones exist only under applied bias.

Abstract

We develop a generalized grand canonical potential for the ballistic nonequilibrium electron distribution in a metal nanowire with a finite applied bias voltage. Coulomb interactions are treated in the self-consistent Hartree approximation, in order to ensure gauge invariance. Using this formalism, we investigate the stability and cohesive properties of metallic nanocylinders at ultrahigh current densities. A linear stability analysis shows that metal nanowires with certain {\em magic conductance values} can support current densities up to 10^11 A/cm^2, which would vaporize a macroscopic piece of metal. This finding is consistent with experimental studies of gold nanowires. Interestingly, our analysis also reveals the existence of reentrant stability zones--geometries that are stable only under an applied bias.