Strain tuning of charge density wave and Mott-insulating states in monolayer VTe₂

Monolayer vanadium ditelluride (VTe₂) exhibits a $2\sqrt{3}\times 2\sqrt{3}$ charge-density-wave (CDW) order intertwined with a Mott-insulating state. However, the physical mechanisms driving the emergence of the CDW order and the Mott-insulating state are still not well understood. In this study, we systematically investigate the electronic band structure, phonon dispersion, and electron–phonon coupling (EPC) of monolayer VTe₂ under applied biaxial strain. Our results reveal that the $2\sqrt{3}\times 2\sqrt{3}$ CDW phase is metastable in free-standing monolayer VTe₂ but becomes stabilized under compressive strain below ε = −2%. The formation of the CDW order originates predominantly from strong EPC, rather than from Fermi-surface nesting. The narrowing of the bandwidth due to the CDW order, combined with correlation effects associated with the V 3d orbitals, collectively drive the system into a Mott-insulating state. Furthermore, we find that tensile strain suppresses the CDW order and induces a superconducting state above a critical strain threshold (ε = 2%). These findings enhance our understanding of correlation physics in monolayer VTe₂ and provide a pathway for strain-engineered manipulation of quantum phases in two-dimensional transition-metal dichalcogenides.