Ultrathin films of Cu on Ru(101¯0): Flat bilayers and mesa islands

► The pseudomorphic Cu films grow in the bilayer-by-bilayer mode. ► For coverage higher than 2 BL, Cu forms 3D islands in mesa shape. ► The mesas have Cu(1 1 1) facets on their tops. ► The facets and the substrate are oriented with Cu(111)||Ru(101¯0)andCu[011¯]||Ru[12¯10].