Adsorption of atomic oxygen, electron structure and elastic moduli of TiC(001) surface during its laser reconstruction: Ab initio study

We have performed ab initio simulation of oxygen atom adsorption on TiC(001) laser-reconstructed surface. Relaxed atomic structures of the O/TixCy(001) surface observed upon thermal impact have been studied. DFT calculations of their thermodynamic, electronic, and elastic properties have been carried out. For the first time we have established the bond length and adsorption energy for various reconstructions of the O/TixCy(001) surface atomic structure. We have examined the effects of the oxygen adatom upon the band and electron spectra of the O/TiC(001) surface in its various reconstructions. For the first time we have established a correlation between the energy level of flat bands (−5.4eV and −5.8eV) responsible for the doublet of singular peaks of partial densities of oxygen 2p electrons, and the adsorption energy of oxygen atom in non-stoichiometric O/TiCy(001) systems. Effective charges of titanium and carbon atoms surrounding the oxygen adatom in various reconstructions have been identified. We have established charge transfer from titanium atom to oxygen and carbon atoms determined by the reconstruction of local atomic and electron structures which correlate with atomic electronegativity values and chemisorption processes. Potential mechanisms for laser nanostructuring of titanium carbide surface have been suggested.