Fig. 3: Born–Oppenheimer energy surface for the \(7\times \sqrt{3}{{{{{{{\rm{R}}}}}}}}3{0}^{\circ }\) structure of 1T-VS2.
From: A full gap above the Fermi level: the charge density wave of monolayer VS2
The axes represent the projection of the full CDW displacement onto the transverse–acoustic (TA) phonon modes at \({{{{{{{\bf{q}}}}}}}}=\pm 9/14\ \overline{{{\Gamma }}{{{{{{{\rm{K}}}}}}}}}\) and the orthogonal complement, which combines all other contributing modes. The full CDW displacement is located at the point (1, 1). The forces resulting from this energy surface are predominantly non-linear and coupled in both directions.
