Atomic-resolution imaging of size-selected platinum clusters on TiO_2(110) surfaces

摘要

Size-selected Ptn (n=4,7–10,15) clusters were deposited on TiO_2(110)-(1×1) surfaces and imaged at atomic resolution using an ultrahigh-vacuum scanning tunneling microscope with a carbon nanotube tip. Clusters smaller than Pt_7 lay flat on the surface with a planar structure and a planar-to-three-dimensional transition occurred at n=8 for Pt_n clusters on TiO_2. However, both Pt_8 and Pt_9 had two types of geometric structures. The geometric structures depend strongly on the number of atoms in the deposited cluster possibly because of the differences in binding energies in different-sized clusters and different degrees of interaction with the surface. We obtained atomic-resolution images of size-selected clusters on surfaces for the first time, enabling the identification of atomic alignments in the clusters on the surface.