Adsorption of Sm and Gd on the Mo(1 1 1) face

Abstract

Adsorption and thermal stability of Sm and Gd thin layers on Mo(1 1 1) surface was investigated using Auger electron spectroscopy (AES), low electron energy diffraction (LEED), scanning tunneling microscopy (STM), X-ray photoemission spectroscopy and work function change measurements (Δ ϕ). At 300 K the first three layers of Sm grows in the monolayer-by-monolayer mode. Sm forms initially a pseudomorphic layer of trivalent atoms, which is probably completed to a densely packed layer in part by divalent Sm atoms. In contrast, the second Sm monolayer is entirely composed of divalent atoms. Gd also grows in the monolayer-by-monolayer mode in the investigated coverage range. At higher temperatures (800 K for Gd and 530 K for Sm) only the first layer is thermally stable. Both adsorbates did not cause surface reconstruction or faceting