V 3 d and Se 4 p spectral reconstruction by charge density wave formation in VSe 2 probed by angle-resolved photoemission spectroscopy

The electronic structure of VSe2 with 4 x 4 x 3.18 charge density wave (CDW) transition has been studied by means of angle-resolved photoemission spectroscopy (ARPES) and scanning photoemission microscopy (SPEM). The partial depletion of the Fermi surfaces is observed in the CDW phase by ARPES, consistent with that reported previously. A flat band with V 3d3z(2)-r(2) character, which is observed near the Fermi level around the Gamma point in the Brillouin zone, gains its spectral weight in the CDW phase while the holelike band around the A point loses its weight. The spectral weight redistribution across the CDW transition indicates an important role of the V 3d-Se 4p hybridization, associated with the out-of-plane displacement of Se reported by Petkov et al. [Phys. Rev. B 111, 014105 (2025)]. The electronic inhomogeneity observed by SPEM suggests different surface terminations of the CDW state with the strong lattice and electronic modulation along the out-of-plane direction.