Competition between strain and chemistry effects on adhesion of Si and SiC

We use ab initio calculations to demonstrate that adhesion of Si and SiC depends on the interplay between surface strain and chemistry. We discover that work of adhesion of Si depends linearly on surface strain. Compressive surface strain increases adhesion, which explains why bare Si-terminated SiC has larger adhesion than Si. However, with as little as one monolayer of oxygen coverage, adhesion of SiC becomes negligible while adhesion of Si remains finite irrespectively of the specific oxygen configuration. This effect is due to fundamental differences between reactivities of Si and SiC during the early stages of oxidation.