Forces of a Pt adatom on a Pt(100) surface by the embedded-atom method

Abstract

The perpendicular forces acting on Pt adatoms from Pt(100) surfaces are presented using the embedded-atom method. The force maps are classified into four force regions. When the adatom is very close to the surface the force is repulsive (region 1). The most repulsive forces represent the corresponding first layer atoms. Contrary to these true atomic images, when the adatom is near the surface and the force is attractive (region 2), there is a build up of the least attractive force peaks among the first layer atoms and the positions above the first atoms are surrounded by the four least attractive force peaks. When the force is strongly attractive (region 3), stronger attractive forces are not found directly above the first layer atoms, but are located above the second layer atoms. When the adatom is far from the surface and the force is weakly attractive (region 4), stronger attractive forces are found above the first layer atoms. In general, the complicated force maps caused by the many-body interactions appear in the attractive regions, which has not been seen in early calculations using pair-wise potentials.