The family of vanadium chalcogenides with variable stoichiometry and abundant crystallographic structures are promising platforms for realizing exotic emergent phenomena. Here, we report on a novel two-dimensional (2D) tetragonal structure of vanadium telluride (VTe) grown by molecular beam epitaxy. The atomic structures and electronic properties are revealed by scanning tunneling microscopy and first-principles calculations. Different from the hexagonal or trigonal lattices of 2D VTe₂, the 2D VTe with a V:Te ratio of 1:1 exhibits an uncommon square lattice. Non-zero differential conductivity at the Fermi energy detected by scanning tunneling spectroscopy reveals the metallic feature of VTe. Meanwhile, Friedel oscillations are observed near chiral point defects and domain walls, illustrating the itinerant nature of the electrons close to the Fermi energy. Our first-principles structure searches identify a 2D body-centered cubic (bcc)-like structure with a favorable formation energy to be the candidate of the metallic phase of the tetragonal VTe obtained experimentally. Based on our calculations the 2D bcc-like structure possesses a strong 2D antiferromagnetic order. Our work enriches the family of vanadium chalcogenides and provides a possible 2D antiferromagnetic material for fabricating advanced spintronic devices.

Vanadium dichalcogenides have attracted increasing interests for the charge density wave phenomena and possible ferromagnetism. Here, we report on the multiphase behavior and gap opening in monolayer VTe₂ grown by molecular beam epitaxy. Scanning tunneling microscopy (STM) and spectroscopy study revealed the (4×4) metallic and gapped (2 $\sqrt{3}$ ×2 $\sqrt{3}$ ) charge-density wave (CDW) phases with an energy gap of ~ 40 meV. Through the in-plane condensation of vanadium atoms, the typical star-of-David clusters and truncated triangle-shaped clusters are formed in the (4×4) and (2 $\sqrt{3}$ ×2 $\sqrt{3}$ ) phases respectively, resulting in different surface morphologies and electronic structures as confirmed by density functional theory (DFT) calculations with on-site Coulomb repulsion. The CDW-driven reorganization of the atomic structure weakens the ferromagnetic superexchange coupling and strengthens the antiferromagnetic exchange coupling on the contrary, suppressing the long-range magnetic order in monolayer VTe₂. The electron correlation is found to be important to explain the gap opening in the (2 $\sqrt{3}$ ×2 $\sqrt{3}$ ) phase.