A method of preparing an ultra-flat metal surface involves providing a layer of a crystalline metallic material on an ultra-flat substrate surface that is relatively harder than the metallic material layer and then impinging the metallic material layer with incoming metal atoms that are deposited as an additive crystalline layer thereon, wherein at least a lattice constant of the additive crystalline layer is different enough from a lattice constant of the crystalline metallic material layer resulting in a reduction of roughness of the surface of the metallic material layer adjacent to the substrate surface. The metallic material layer having an ultra-flat surface then is separated by template stripping or other technique from the substrate surface for further use of the ultra-flat surface.