Work Functions of Cathode Surfaces with Adsorbed Atoms Based on Ab Initio Calculations

Work function is one of the most fundamental electronic properties of a metallic surface. The calculation of work function in our work were performed using density functional theory in the local density approximation, with a plane wave basis set and ultra-soft pseudopotentials or the projector-augmented wave method, as implemented in the Vienna ab-initio simulation package. We put another two tungsten layers and 1 or 2 atomic layers of barium on the bulk in sequence. A preliminary ab initio calculation shows that the work function of the tungsten substrate could be lowered obviously due to the adsorbed atoms distributed onto a W(001) surface.