The influence of surface roughness on electrical conductance of thin Cu films: An ab initio study

First-principles calculations show that atomic-scale surface roughness dramatically affects the electrical conductivity of thin films. Atomic clusters, 1–3 atoms high, deposited on the flat Cu(001) surface of an 11 monolayer thick film lead to a 30−40% reduction of its conductance. This is attributed to the destruction of isotropic Fermi surface sheets. We provide a simple parametrized formula, correlating the size of the surface added structures to the film conductance, and also demonstrate that Ta and Al surface monolayers on rough Cu surfaces cause a conductance decrease and increase, respectively.