Quantum Necking in Stressed Metallic Nanowires

TL;DR

This paper explores the unique behavior of metallic nanowires under stress, revealing complex shape evolution driven by electron-shell effects and predicting universal equilibrium forms.

Contribution

It introduces a PDE model for nanowire shape evolution incorporating electron-shell effects, highlighting novel dynamics and equilibrium shapes at the nanoscale.

Findings

Identification of kink dynamics in nanowire shape evolution

Prediction of universal equilibrium nanowire shapes

Demonstration of fluid dynamics concepts in nanoscale materials

Abstract

When a macroscopic metallic wire is subject to tensile stress, it necks down smoothly as it elongates. We show that nanowires with radii comparable to the Fermi wavelength display remarkably different behavior. Using concepts from fluid dynamics, a PDE for nanowire shape evolution is derived from a semiclassical energy functional that includes electron-shell effects. A rich dynamics involving movement and interaction of kinks connecting locally stable radii is found, and a new class of universal equilibrium shapes is predicted.