Origin of surface stress on late transition metal surfaces:Ab initiolocal stress and tight-binding model

Abstract

We present a stress model, ``the Friedel stress'' model, based on the second-moment tight-binding approach, as a quantitative model of in-plane surface stress on transition metal surfaces. By comparing the results obtained with the stress model and ab initio local stress calculation on fcc (111) surfaces, we demonstrate that the in-plane surface stress originates from a surface $d$-band width change due to the reduced coordination number. This indicates that surface stress can occur without the direct effects of charge redistribution, which is widely accepted as the origin of surface stress. The variation in in-plane stress induced by the strain parallel to the surface is also reproduced correctly by the Friedel stress, which further proves the dependence of surface stress on the surface $d$-band width. We demonstrate that surface stress has a strong correlation with the surface chemical reactivity mediated by the surface $d$-band behavior.