Charge density wave states in phase-engineered monolayer VTe₂

Charge density wave (CDW) strongly affects the electronic properties of two-dimensional (2D) materials and can be tuned by phase engineering. Among 2D transitional metal dichalcogenides (TMDs), VTe_2 was predicted to require small energy for its phase transition and shows unexpected CDW states in its T-phase. However, the CDW state of H-VTe_2 has been barely reported. Here, we investigate the CDW states in monolayer (ML) H-VTe_2, induced by phase-engineering from T-phase VTe_2. The phase transition between T- and H-VTe_2 is revealed with x-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM) measurements. For H-VTe_2, scanning tunneling microscope (STM) and low-energy electron diffraction (LEED) results show a robust 2\sqrt 3 \times 2\sqrt 3 CDW superlattice with a transition temperature above 450 K. Our findings provide a promising way for manipulating the CDWs in 2D materials and show great potential in its application of nanoelectronics.