Electronic structure and physical properties of oxygen-adsorbed TiC and low-defects TixCy(111) surfaces: A first principle calculations

We used ab initio calculations to systematically investigate the atomic structure, electronic and thermodynamic properties of oxygen-adsorbed TiC(111) surface affecting its potential reconstructions. Using the density functional theory, we study various degrees of coverage with the oxygen of TiC(111) surface in fcc position, which is in reconstructions of TiC(111)-(3×3)R30-O and TiC(111)-(1 × 1)-O. A considerable rearrangement has been established in the local atomic structure of O/TiC(111) surface depending upon the degree of its coverage with atomic oxygen in fcc stacking position. We demonstrated that the distance between adsorbate and TiC(111) surface decreases with the increase of its coverage with oxygen. We also examined the effects of the oxygen adatom upon the band and electron spectra of the O/TiC(111) surface in its various reconstructions. Effective charges of titanium and carbon atoms surrounding the oxygen adatom in various reconstructions have been identified. We established charge transfer from titanium atom to oxygen and carbon atoms determined by the reconstruction of local atomic and electron structures and correlating with their electronegativity values and chemisorption processes. Potential mechanisms for laser nanostructuring of titanium carbide surface have been suggested.