Dislocation nucleation on a near surface void leading to surface protrusion growth under an external electric field

Abstract

The stress exerted on a conducting material surface by an external electric field can cause plastic deformation if the stress is concentrated somewhere in the material. Such concentration can occur due to the presence of a near surface void. The plastic deformation can lead to growth of a protrusion on the surface. To investigate the conditions where such a mechanism can operate, we employ concurrent electrodynamics-molecular dynamics simulations, analyze the distribution of stress near the void by using both the molecular dynamics and finite element method, and compare the result to the analytical expression for a void located deep in the bulk. By applying an electric field of exaggerated strength we are able to simulate the plastic deformation process within the timespan allowed by molecular dynamics simulations. In reality, longer timespans would allow for the initiation of the proposed mechanism at electric field strengths much lower than the values assumed for the simulations in the present work.