Simple approach to current-induced effects -- bond weakening in metal chains

TL;DR

This paper introduces a simple first-principles method to estimate current-induced stresses in bulk systems under ballistic conditions, demonstrated on 1D metal chains, revealing stability trends consistent with experimental break voltages.

Contribution

The paper presents a novel, computationally efficient scheme for calculating nonequilibrium mechanical properties of bulk systems under current, focusing on bond weakening in metal chains.

Findings

Gold is most stable under high current

Aluminum is least stable under high current

The method agrees with experimental break voltage trends

Abstract

We present a simple, first principles scheme for calculating mechanical properties of nonequilibrium bulk systems assuming an ideal ballistic distribution function for the electronic states described by the external voltage bias. This allows for fast calculations of estimates of the current-induced stresses inside bulk systems carrying a ballistic current. The stress is calculated using the Hellmann-Feynman theorem, and is in agreement with the derivative of the nonequilibrium free energy. We illustrate the theory and present results for one-dimensional (1D) metal chains. We find that the susceptibility of the yield stress to the applied voltage agrees with the ordering of break voltages among the metals found in experiments. In particular, gold is seen to be the most stable under strong current, while aluminum is the least stable.