Role of sulfur in BaVS3 probed by S K-edge absorption spectroscopy

Abstract

We show that the quasi-1D behavior of BaVS 3 can be understood analyzing the X-ray absorption near edge spectra at the sulfur K edge. Linear dichroïsm experiments, analyzed with the help of ab initio calculations, reveal two strong and polarization dependent pre-edge features, induced by the band character of the 3d vanadium levels. They are related to crystal field split t 2g and e g states. When the temperature is lowered, the t 2g feature shifts progressively to higher energy, and its intensity increases for the polarization along the c-axis, stacking direction of the V-S face sharing octahedra. This behavior points to the depletion of sulfur states and thus the lack of S 3p -V 3d hybridization in the direction of V-S chains.

Soft-phonon driven hexagonal-orthorhombic phase transition in BaVS3

“…For non stoichiometric BaVS 3-δ , the Peierls distortion is replaced by an incommensurate modulation due to a charge ordering associated with the localized E g electrons 33,34 . Finally, linear dichroism experiments have pointed out the progressive depletion of S 3p z -V 3d z 2 hybridization associated with the zig-zag deformation of VS 6 octahedra chains 35 .…”