Adhesion of thin metallic layers on Au surfaces

Abstract

We carried out first-principle calculations to study the work of separation for five different metal-metal interfaces, each of them comprising thin layers of selected metals (Cr,W,Ta,Al or Ti) lying on top of Au surfaces. We found that the highest work of separation is obtained for 1-atom-thick layers. Increasing the number of atomic layers by a few units leads the work of separation to oscillate with the thickness; its value then flattens for a large number of layers.Interestingly, for most cases the lowest work of separation is obtained for two-atom layers. We find that such a behavior is reflected into the amount of charge transfer between the two metals on the one hand, and their spatial distance on the other.