Effect of metal and carbon vacancies on the band structure of hexagonal tungsten carbide

The band structure of hexagonal tungsten carbide (beta -WC) containing vacancies in metal and carbon sublattices is investigated within the first-principles full-potential linear muffin-tin orbital (LMTO) approach for a model of 16-atom supercells. Specific features of the formation of vacancy states are discussed, and the formation energies of defects and their charge states are estimated. The results obtained are compared with previous calculations and available experimental data. (C) 2001 MAIK Nauka/Interperiodica.