First-principles study of W, N, and O adsorption on TiB2(0001) surface with disordered vacancies

In this paper, we systematically investigate the adsorption properties, atomic structures, electronic, and thermodynamic properties of tungsten, nitrogen, and oxygen atoms on the Ti-terminated TiB2(0001) surface without and with vacancies of titanium and boron atoms using the density functional theory (DFT). Local atomic structures of the surfaces R/TiB2(0001) (R = W, N, O) of adsorption models and their thermodynamic and electronic properties are studied by DFT. The bond lengths and the adsorption energy for different reconstructions of the atomic surface of the R/TiB2(0001) systems are established. The role of the degree of coverage of W, N and O atoms on the electronic structure and mechanisms of their adsorption on the surface (0001) of titanium diboride is investigated. We also consider the mechanisms of possible nucleation of tungsten on the surface of TiB2(0001). Effective charges on the tungsten atom (N and O) and nearest-neighbor atoms in the studied reconstructions are estimated. Our calculations show that the charges are transferred from the titanium atom to the W, N, and O atoms, which are due to the reconstruction of the local atomic and electronic structures and correlates with the electronegativity of the nearest-neighbor atoms. © 2018 Elsevier Ltd