Transition Metal Dichalcogenides Layers with the Strain and the Charge Density Wave Order: Wannier Electronic Structure Modeling*

With the development of the experimental techniques to synthesize and characterize the two-dimensional van der Waals layered materials, intense theoretical investigations have been focusing on the potential device applications. On the other hand, the layered geometry also provides a platform to study the correlated many-body physics in the reduced dimensionality. Among different layer types, the transition metal dichalcogenides are an interesting class of materials which come in various flavors for the structural and electronic properties. Many of them such as TaS2 crystals exhibit charge density wave order and superconductivity. To utilize the layer platform to study the interaction between different electronic orders and their mechanism, it is crucial to have a solid picture of the underlying electronic structure. In our modeling work, the Wannier function method is applied to derive these electronic models without any ad hoc fitting procedures. These Hamiltonians shed light on the physics of the strain and the charge density wave order in the layers, and serve as the starting point for more elaborated many-body theory and ab initio numerical simulations.