Adsorption and diffusion of an alkali-metal adatom on transition-metal dichalcogenides

摘要

Employing total-energy density-functional theory calculations the adsorption energies, the diffusion pathways, and the barriers for a Li adatom on stepped TiSe_2 surfaces with full relaxation of the atomic environment were studied. The minimum-energy paths for Li diffusion on a TiSe_2 (0001) surface and across the (1010) and (1211) steps have been calculated. At the (1211) step edge an Ehrlich-Schwoebel barrier of 0.31 eV was obtained, which is additional to the diffusion barrier of 0.25 eV on the flat surface. The energies for subsequent diffusion within the van der Waals gap have been calculated, too.