A density functional study on the electronic structures of TiX (X = C, N, O). Part II. Investigations on the electronic structures of TiC bulk and surfaces

摘要

Using the DFT/BLYP method, the electronic structures of TiC and TiO bulk have been investigated, and some physical properties of this class of compounds are also discussed. The band structure calculations for the TiC(001) surface have also been performed. Due to the more covalent overlap between Ti and C atoms, the TiC(001) surface is inactive for the surface reactions in comparison with the TiN(001) surface. In our calculated results of the TiC(111) surface, the doublet structure observed at just below E_F in ARPES studies is well reproduced and the constituents of this feature are identified. The sharp peak located just below E_F consists mainly of the 3d_z~2 orbital of surface Ti and it can be ascribed to an "active" surface state. Another peak, which is insensitive to the surface reactions, is derived mainly from the 3d_(x~2-y~2)/3d_(xy) orbitals of surface Ti.