Li on S covered Ni(1 0 0) surfaces

Abstract

In this paper we study the interaction of Li with S-covered Ni(1 0 0) surfaces at room and elevated temperatures, with low energy electron diffraction, Auger electron spectroscopy, thermal desorption spectroscopy and work function measurements. On clean Ni(1 0 0) Li forms an order layer up to 0.5 ML, whereas at higher coverages it causes a restructuring of the surface with possible formation of Li–Ni alloy. At high coverages the Li overlayer becomes metallic. Lithium on S-covered Ni(1 0 0) interacts strongly and destabilizes the S–Ni bound. The Li–S interaction increases the ionicity of Li on the surface and leads to Li–S compounds formation. The Li–S compound formation give a low work function surface system on Ni(1 0 0). Sulphur passivates the Ni(1 0 0) surface against the restructuring caused by the Li deposition.