On the Stability and Structural Dynamics of Metal Nanowires

TL;DR

This paper reviews the nanoscale free-electron model to understand the stability and dynamics of metal nanowires, highlighting the roles of surface and quantum-size effects, and identifying stable configurations and their lifetimes.

Contribution

It provides a linear stability analysis and nonlinear simulations to elucidate the structural stability and evolution of metal nanowires based on quantum and surface effects.

Findings

Certain conductance values correspond to exceptionally stable nanowires.

Universal equilibrium shapes include a magic cylinder with unduloidal contacts.

Lifetimes of metastable nanowire structures are quantitatively estimated.

Abstract

This article presents a brief review of the nanoscale free-electron model, which provides a continuum description of metal nanostructures. It is argued that surface and quantum-size effects are the two dominant factors in the energetics of metal nanowires, and that much of the phenomenology of nanowire stability and structural dynamics can be understood based on the interplay of these two competing factors. A linear stability analysis reveals that metal nanocylinders with certain magic conductance values G=1, 3, 6, 12, 17, 23, 34, 42, 51, 67, 78, 96, ... times the conductance quantum are exceptionally stable. A nonlinear dynamical simulation of nanowire structural evolution reveals a universal equilibrium shape consisting of a magic cylinder suspended between unduloidal contacts. The lifetimes of these metastable structures are also computed.