A search for an atomically flat Pb surface and an outlook on CO manipulation on Pb

Abstract

Scanning tunnelling microscopy can be used to study metal surfaces on an atomic level. An interesting metal to study is lead because it is superconducting below 7.2 K. With a scanning tunnelling microscope single molecules like CO can be manipulated to build artificial structures. These structures confine the electrons and hence give rise to specific energy bands. Before measurements can be done the metal surface has to be atomically flat. The creation of atomically flat Pb(111) and Pb(100) was attempted using etching, sputtering and annealing. Atomically flat lead surfaces were not yet obtained. An outlook on the possibility of manipulating CO on Pb(111) is explored using density functional theory calculations. The results were compared with density functional theory calculations of CO on Au(111) and CO on Cu(111). The CO does not bind directly above an Pb atom at the surface, but does bind in both bridge- and three-fold hollow sites of the Pb surface. The calculated binding energies are comparable to the binding energy of CO on Cu(111). This suggests that atomic scale manipulation of CO on Pb is possible.