Strong correlation between surface stress and mechanical strain in Cu, Ag and Au

¹ School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology Ulsan 689-798, South Korea
² Department of Mechanical Engineering, Ulsan College - Ulsan 680-749, South Korea
³ Multiscale and Multiphysics Simulations Group and Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology - Ulsan 689-798, South Korea

^(a) sykim@unist.ac.kr (corresponding author)

Received: 9 January 2014
Accepted: 14 April 2014

Abstract

The surface stress, in addition to the surface energy and elastic modulus, is a fundamental measure of the surface effects in a nanostructure. Here, we investigate the strong correlation between the surface stress and mechanical strain in three noble-metal (001) surfaces. For this investigation, we have developed a simple and efficient method to calculate the surface stress directly from the strained configurations in molecular statics simulations. While the surface stress of the copper (001) surface along the strained direction is almost constant, that of the gold (001) surface decreases drastically as the strain increases. We explain these different responses of the surface stress to strain in terms of the different surface relaxation occurring in different noble-metal nanoplates.