Monolayer VTe_2: Incommensurate Fermi surface nesting and suppression of charge density waves

摘要

We investigated the electronic structure of monolayer VTe2 grown on bilayer graphene by angle-resolved photoemission spectroscopy (ARPES). We found that monolayer VTe2 takes the octahedral 1T structure in contrast to the monoclinic one in the bulk, as evidenced by the good agreement in the Fermi surface topology between ARPES results and first-principles band calculations for octahedral monolayer 1T-VTe2. We have revealed that monolayer 1T -VTe2 at low temperatures is characterized by a metallic state whereas the nesting condition is better than that of isostructural monolayer VSe2 which undergoes a charge density wave (CDW) transition to an insulator at low temperatures. The present result suggests an importance of the Fermi surface topology for characterizing the CDW properties of monolayer transition-metal dichalcogenides.