Stability and Symmetry Breaking in Metal Nanowires

TL;DR

This paper presents a continuum stability analysis of metal nanowires, revealing that while cylinders are generally stable, various symmetry-breaking structures emerge at low conductance, influenced by surface and quantum effects.

Contribution

It introduces a comprehensive linear stability framework for metal nanowires that incorporates material-specific surface and quantum-size effects, highlighting the stability of non-cylindrical structures.

Findings

Cylinders are the only generically stable nanowire shape.

Multiple symmetry-breaking structures are stable at low conductance.

Material properties influence the stability of non-cylindrical nanowires.

Abstract

A general linear stability analysis of simple metal nanowires is presented using a continuum approach which correctly accounts for material-specific surface properties and electronic quantum-size effects. The competition between surface tension and electron-shell effects leads to a complex landscape of stable structures as a function of diameter, cross section, and temperature. By considering arbitrary symmetry-breaking deformations, it is shown that the cylinder is the only generically stable structure. Nevertheless, a plethora of structures with broken axial symmetry is found at low conductance values, including wires with quadrupolar, hexapolar and octupolar cross sections. These non-integrable shapes are compared to previous results on elliptical cross sections, and their material-dependent relative stability is discussed.