Revealing flat bands near the Fermi level in 1T−VSe2 by using angle-resolved photoemission spectroscopy

Here, we study the surface electronic structure of $1T\text{\ensuremath{-}}\mathrm{V}{\mathrm{Se}}₂$ by means of angle-resolved photoemission spectroscopy and uncover a dispersionless emission located in the vicinity of the Fermi level. Its crystal momentum dependency reveals that it occupies large portions of the Brillouin zone, where no bulk band is expected. Upon electron doping (deposition of Rb atoms), the system evolves in a surprising way. Besides the expected down-shifting of the bands, a splitting of both bulk and dispersionless emission is observed. This peculiar behavior strongly suggests the intrinsic nature of the dispersionless emission. Its characterization may therefore be relevant to a deeper understanding of the physics of transition metal dichalcogenides.