The electronic structure of some monovalent-metal intercalates of TiS₂

The electronic structures of the layered compound TiS₂ and its intercalates LiTiS₂, NaTiS₂ and AgTiS₂ are calculated using the ASW method. Various deviations from the rigid-band model are observed, of which the increase of the Ti-3d/S-3p gap and the variation of the inter-sandwich and intra-sandwich interactions between S-3p orbitals are the most pronounced. The effect of the flattening of the TiS₂ slabs-such as occurs at the 3R(I)-3R(II) transition in Na_xTiS₂ for x approximately=0.7-on the electronic structure is calculated for Na₁TiS₂ and is shown to be coupled with an increased ionicity in the Ti-S bond.