Abstract
Transition metal dichalcogenide (TMD) bilayers have recently emerged as a robust and tunable moiré system for studying and designing correlated electron physics. In this Rapid Communication, by combining a large-scale first-principles calculation and continuum model approach, we provide an electronic structure theory that maps long-period TMD heterobilayer superlattices onto diatomic crystals with cations and anions. We find that the interplay between the moiré potential and Coulomb interaction leads to filling-dependent charge transfer between different moiré superlattice regions. We show that the insulating state at half filling found in recent experiments on WSe2/WS2 is a charge-transfer insulator rather than a Mott-Hubbard insulator. Our work reveals the richness of simplicity in moiré quantum chemistry.
| Original language | English |
|---|---|
| Article number | 201115 |
| Journal | Physical Review B |
| Volume | 102 |
| Issue number | 20 |
| DOIs | |
| State | Published - Nov 30 2020 |
Funding
We thank Kin Fai Mak and Jie Shan for sharing their experimental results with us prior to publication, and Hiroki Isobe, Zhen Bi, Taige Wang, Long Ju, and Feng Wang for helpful discussions. This work is supported by DOE Office of Basic Energy Sciences under Award No. DE-SC0018945, N.Y. was partly supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-SC0020149.