Experimental electronic structure and Fermi-surface instability of the correlated 3d sulphide BaVS3: High-resolution angle-resolved photoemission spectroscopy

The correlated $3d$ sulphide $\mathrm{Ba}\mathrm{V}{\mathrm{S}}_{3}$ exhibits an interesting coexistence of one-dimensional and three-dimensional properties. Our experiments determine the electronic band structure and shed light on this puzzle. High-resolution angle-resolved photoemission measurements in a $4\text{\ensuremath{-}}\mathrm{eV}$-wide range below the Fermi energy level uncover and investigate the coexistence of ${a}_{1g}$ wide-band and ${e}_{g}$ narrow-band $d$ electrons, which lead to the complicated electronic properties of this material. We explore the effects of strong correlations and the Fermi surface instability associated with the metal-insulator transition.