Variable Curvature Slab Molecular Dynamics as a Method to Determine Surface Stress

TL;DR

This paper introduces a novel molecular dynamics method that models surface stress-induced bending in thin slabs by incorporating curvature as a dynamic variable, enabling detailed surface stress analysis.

Contribution

The paper develops a classical MD formulation with variable curvature as a dynamical degree of freedom, allowing surface stress effects to be simulated explicitly.

Findings

Method successfully applied to Au surfaces with different conditions

Demonstrates capability to model surface phenomena involving stress and curvature

Provides a new tool for studying surface-induced mechanical effects

Abstract

A thin plate or slab, prepared so that opposite faces have different surface stresses, will bend as a result of the stress difference. We have developed a classical molecular dynamics (MD) formulation where (similar in spirit to constant-pressure MD) the curvature of the slab enters as an additional dynamical degree of freedom. The equations of motion of the atoms have been modified according to a variable metric, and an additional equation of motion for the curvature is introduced. We demonstrate the method to Au surfaces, both clean and covered with Pb adsorbates, using many-body glue potentials. Applications to stepped surfaces, deconstruction and other surface phenomena are under study.