Interaction of Li with the group IV selenide layer compounds at low temperature

Li was deposited at low temperature (80 K) onto cleaved van der Waals surfaces of the layered compounds MSe2 (M≡Ti, Zr and Hf). The adsorption systems were investigated by means of low-energy electron diffraction, work-function measurements and soft-x-ray photoelectron spectroscopy using a synchrotron radiation source. The results suggest that at low coverages, Li is uniformly distributed near the surface, leading via a decomposition reaction to the formation of Li2Se and M0. At high adsorbate concentration, some of the Li intercalates into the substrate in the interlayer region. The intercalation process seems to depend on the temperature and the lattice parameter of the substrate. (author)