Angle-resolved photoemission study of Ni-intercalated 1T-TiS2

Angle-resolved photoemission spectra have been measured to study the electronic structures of Ni intercalated layered compound ${\mathrm{Ni}}_{1/3}{\mathrm{TiS}}_{2}.$ The results have shown that some new bands appear in ${\mathrm{Ni}}_{1/3}{\mathrm{TiS}}_{2}$ and the dispersions of most other bands are strongly modified compared with ${\mathrm{TiS}}_{2}.$ It is clarified that the new band near the Fermi level ${(E}_{F})$ is the split-off state or the bonding state between the final states originating from the $|{d}^{1}{(t}_{2g})〉$ and $|{d}^{2}{(t}_{2g}{,e}_{g})L〉$ initial states, where $L$ stands for the $\mathrm{S}3p$ hole state. Another new band observed at \ensuremath{\sim}1 eV below ${E}_{F}$ is hardly dispersive and attributed to the $\mathrm{Ni}{3d}_{{z}^{2}}\ensuremath{-}\mathrm{Ti}{3d}_{{z}^{2}}$ bonding state. The $\mathrm{Ni}3d``{e}_{g}''\ensuremath{-}\mathrm{S}3p$ bonding states are observed in the larger binding energy region. Knowledge of hybridizations among the $3d$ states of the intercalant, $\mathrm{Ti}3d$ states, and $\mathrm{S}3p$ states are essential to interpret the physical properties of ${\mathrm{Ni}}_{1/3}{\mathrm{TiS}}_{2}.$