Room temperature charge density wave in vanadium ditelluride (VTe₂)

Layered transition metal chalcogenides (TMDs) have been extensively studied in terms of spontaneous lattice distortion such as charge density wave (CDW). In the layered crystals, new order parameters such as flake thickness, defect density and carrier density have been newly used to trigger CDW phase transition. While device applications require room temperature manipulation of the CDW, switching CDW in TMDs at room temperature remains a challenge. We report vanadium ditelluride (VTe₂) synthesized by flux method, which shows CDW transition at T=420 K. Since the transition temperature is above the temperature, a distorted lattice structure (monoclinic and C2/m) was observed in our VTe₂ at room temperature. Above the T=420 K, the lattice structure changes to a trigonal structure having a higher symmetry. We verified the CDW state by electrical transport measurement, powder and single crystal X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The single-crystalline VTe₂ exhibits metallic transport characteristics at room temperature which is unique compared to other group 5 TMDs.