Interplay between ordered growth and intermixing of Pt on patterned Au surfaces

We have investigated the growth of submonolayer coverage of platinum on two gold surfaces (Au(1 1 1) and Au(7 8 8)), at temperatures ranging from 110 K to 300 K. The Scanning Tunneling Microscope images reveal a competition between the ordered growth of nanodots and a random intermixing between Pt and Au. The Pt deposition on the Au(1 1 1) surface at room temperature shows an ordered growth limited by the insertion of Pt atoms into the surface layer and the subsequent modifications of the herringbone surface pattern. In contrast, for Pt on the Au(7 8 8) stepped surface, perfect ordered growth is observed over a wide temperature range.