Further theoretical analyses (2D and 3D) of Ni1/4TiS2 probed by XPS/STM studies

Isabelle Baraille (1) , Hervé Martinez (1) , Yann Tison (1) , Danielle Gonbeau (1) , Michel Loudet (1)

1 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

The surface of Ni1/4TiS2 was investigated by X-ray photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). Electronic calculations were performed using the ab initio Hartree-Fock program crystal. The XPS results (chemical shift of core peaks) are satisfactorily accounted for through a Mulliken population analysis. Concerning the STM results, we imaged the top sulfur plane (0 0 1) and interpret the data on the basis of the partial electron density of a slab which consist of seven (0 0 1) Ni1/4TiS2 layers. It was found that the bright spots in experimental STM images correspond to sulfur atoms in a single metallic environment (Ti atoms). Beside higher electronic density, these atoms are highlighted because of their proximity to the tip compared with sulfur atoms in a double environment (Ti and Ni).

Mots clés: Ab initio quantum chemical methods and calculations; X-ray photoelectron spectroscopy; Scanning tunneling microscopy; Density functional calculations

Domaines: Chimie; Matériaux

Isabelle Baraille, Hervé Martinez, Yann Tison, Danielle Gonbeau, Michel Loudet. Further theoretical analyses (2D and 3D) of Ni1/4TiS2 probed by XPS/STM studies. Surface Science : A Journal Devoted to the Physics and Chemistry of Interfaces, 2002, 517 (1-3), pp.43--51. ⟨10.1016/S0039-6028(02)01883-6⟩. ⟨hal-01498396⟩