Strong Metal–Sulfur Hybridization in the Conduction Band of the Quasi-One-Dimensional Transition-Metal Trichalcogenides: TiS₃ and ZrS₃

The elemental contributions to the conduction bands of the transition-metal trichalcogenides TiS3 and ZrS3 were examined using X-ray absorption spectroscopy, at the Ti and S 2p edges and the Zr 3p edges. A comparative study of these two compounds shows that the bottom of the conduction band, for both TiS3 and ZrS3, is comprised mainly of hybridized transition metal-sulfur orbitals, either Ti 3d and S 3p orbitals or Zr 4d and S 3p orbitals. Density functional theory and experiment both indicate that the bottom of the conduction band, in the case of TiS3, has the Ti 3d weight. Although weak, experiment indicates that the S-weighted contribution to the conduction band minimum for ZrS3 is greater than in the case of TiS3. For ZrS3, theory, however, indicates that the conduction band is dominated by hybridization of the Zr 4d and S 3p orbitals, including in the vicinity of the bottom of the conduction band.