Accurate <i>ab-initio</i> tight-binding model for twisted transition metal dichalcogenide bilayers

The discovery of correlated and superconducting states in magic-angle twisted bilayer graphene has generated interest in twisted heterostructures composed of other 2D materials. For example, signatures of superconductivity [1-2] and exotic optical behaviour [3] have been observed recently in twisted bilayers of transition metal dichalcogenides (TMDs).

The theoretical and computational study of these materials using first-principles methods, however, remains challenging due to their large Moiré superlattice sizes at small twist angles. In this work, we develop accurate and efficient tight-binding models for predicting and understanding the electronic structure of twisted TMD heterostructures. We extend the first-principles TMD tight-binding model of Fang et al. [4] to twisted and hetero-bilayer structures. We demonstrate the importance of including additional interlayer interactions between p_z and d_z² orbitals and validate our model by benchmarking against large-scale DFT calculations on larger angle twisted bilayer TMDs.

[1] Wang L. et al., Nat. Mat. 19, pages 861–866 (2020)
[2] An L. et al., Nanoscale Horiz. 5, 1309-1316 (2020)
[3] Tran, K., et al., Nature 567, 71–75 (2019).
[4] Fang et al., Phys. Rev. B 92, 205108 (2015)