Observation of Electronic Strong Correlation in VTe2-23×23 Monolayer

Strong electron correlation under two-dimensional limit is intensely studied in the transition metal dichalcogenides monolayers, mostly within their charge density wave (CDW) states that host a star of David period. Here, by using scanning tunneling microscopy and spectroscopy and density functional theory calculations with on-site Hubbard corrections, we study the ${\mathrm{VTe}}_{2}$ monolayer with a different $2\sqrt{3}\ifmmode\times\else\texttimes\fi{}2\sqrt{3}$ CDW period. We find that the dimerization of neighboring Te-Te and V-V atoms occurs during the CDW transition, and that the strong correlation effect opens a Mott-like full gap at Fermi energy (${\mathrm{E}}_{\mathrm{F}}$). We further demonstrate that such a Mott phenomenon is ascribed to the combination of the CDW transition and on-site Coulomb interactions. Our work provides a new platform for exploring Mott physics in 2D materials.