Structural, vibrational and electronic properties of the superconductor CuTiSe: theoretical and experimental insights

The crystal/electronic structure and vibrational properties of the Cu x TiSe 2 intercalation compounds were studied combining experimental and theoretical techniques. The Cu added into the TiSe 2 matrix was characterized as an intercalant atom into van der Waals gaps from Raman spectroscopy analysis. Theoretical and experimental data indicate the Cu-intercalation effect on the crystalline structure as a local disorder affecting [TiSe 6 ] clusters from Se Se layers, which results in a volume expansion. A significant charge transfer from Cu atoms to the host lattice results in a change from Ti 4+ to Ti 3+ species, narrowing the band-gap and increasing the superconductivity of the material. The crystal/electronic structure and vibrational properties of the Cu x TiSe 2 intercalation compounds were studied combining experimental and theoretical techniques.