Spectral density of surface states for TiO and VO: (001) surface

We present a calculation of the spectral density of states for crystals of TiO and VO with (001) cleaved surfaces. The transfer matrix formalism is employed, with a hamiltonian including the O 2p and the metal 3d orbitals. Slater-Koster parameters obtained by Mattheiss (1972) from a bulk calculation are used. The results are obtained at three special points in the 2D Brillouin zone for three different (001) planes: surface plane, plane immediately below it and bulk plane. In the neighborhood of the point M there is an intrinsic surface state and a surface resonance due to the hybridization between ligand and metal orbitals. The surface state has mixed e_g and p_z symmetry along the Σ symmetry line and lies above the Fermi level. No surface relaxation or reconstruction is considered.