Excitons arising from generalized Wigner crystal states in moiré superlattices

The recent discovery of generalized Wigner crystal states in transition metal dichalcogenide (TMD) moiré superlattices has opened new avenue for exploring strongly correlated electron systems. [1–3] These generalized Wigner crystal states, formed at fractional electron or hole fillings, exhibit intriguing patterns of charge density distributions that break the original translational symmetry of the moiré superlattices. In this talk, we investigate excitonic effects[4] in generalized Wigner crystals utilizing the ab initio GW plus Bethe-Salpeter equation approach. We will present the computational techniques developed for treating such systems. We will discuss the impact from the ground-state Wigner crystal states on the excited excitonic states in moiré superlattices.



[1] E. C. Regan et al., Mott and generalized Wigner crystal states in WSe2/WS2 moiré superlattices, Nature 579, 359 (2020).

[2] Y. Xu, S. Liu, D. A. Rhodes, K. Watanabe, T. Taniguchi, J. Hone, V. Elser, K. F. Mak, and J. Shan, Correlated insulating states at fractional fillings of moiré superlattices, Nature 587, 214 (2020).

[3] H. Li et al., Imaging two-dimensional generalized Wigner crystals, Nature 597, 650 (2021).

[4] M. H. Naik et al., Intralayer charge-transfer moiré excitons in van der Waals superlattices, Nature 609, 52 (2022).