Ge adsorption on W(100): calculations

For the first time, the adsorption of germanium atoms on the (100) face of tungsten was calculated using the density functional theory. The tungsten substrate was made as a 2D layer. The W 2D layer was modeled by a W(100) 2×2×2 supercell. The calculation of the electron density of state and the adsorption energy of a Ge atom was carried out for three adsorption sites of the Ge atom: in the hollow position, in the bridge position between surface W atoms, and above the surface W atom: one Ge atom per 8 surface W atoms (most preferably adsorption of a germanium atom in hollow position). The adsorption energy is significant: 6,38 eV. The adsorption of Ge atoms leads to an insignificant reconstruction of the W surface: the maximum shift of W atoms does not exceed 0,15 Å. The valence band of the W(100) 2D layer is formed mainly by W 5d electrons, with an insignificant contribution of W 6s electrons. The Ge band is formed by Ge 4p electrons and Ge 4s electrons.