ULTRATHIN FILMS OF RH ON AU(001) AND RH ON AG(001) - GROWTH MODE AND MAGNETISM

Deposition of minute amounts of Rh on a clean and reconstructed Au{001} surface destroys the reconstruction and yields a 1 x 1 structure. Prolonged deposition produces epitaxial but not pseudomorphic films of Rh with the bulk equilibrium fcc structure. Deposition of Rh on a clean Ag{001} surface produces overlayers which are partially covered by or intermixed with Ag, but which arc pseudomorphic with the Ag{001} substrate. Photoemission experiments in the very early stages of over-layer growth reveal a 4.1 +/- 0.3 eV splitting of the 4s levels of Rh, which is not observed in thick Rh films. The 4s splitting is explained by the presence of a magnetic moment on the Rh atoms and is related to recent theoretical predictions of ferromagnetism in a monolayer of Rh on either Ag{001} or Au{001}.