BaVS3 probed by V L edge x-ray absorption spectroscopy.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid-State Chemistry

Background:

• Barium Vanadium Sulfide (BaVS(3)) exhibits complex phase transitions.
• Understanding the electronic and structural properties of BaVS(3) is crucial for materials science applications.

Purpose of the Study:

• To investigate the polarization dependence of vanadium L-edge X-ray absorption spectra in BaVS(3) single crystals.
• To correlate observed spectral changes with the different phases and transitions of BaVS(3).

Main Methods:

• Measurement of polarization-dependent vanadium L-edge X-ray absorption spectra.
• Analysis of linear dichroism (difference between E || c and E ⊥ c polarizations).
• Temperature-dependent measurements across four distinct phases of BaVS(3).

Main Results:

• Significant changes in linear dichroism were observed with temperature variations.
• A new spectral feature emerged in the pre-edge region below the metal-insulator transition.
• Pretransitional charge density wave fluctuations were identified as precursors to spectral changes.
• Symmetry analysis suggests rearrangements in E(g) and A(1g) states, consistent with four inequivalent V-sites.

Conclusions:

• The study reveals temperature-induced structural and electronic modifications in BaVS(3).
• Observed spectral changes are strongly linked to charge density wave dynamics and site symmetry.
• The findings support a model of four inequivalent vanadium sites forming along the V-S chain in certain phases.