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arXiv · 1910.14061

Moiré quantum chemistry: charge transfer in transition metal dichalcogenide superlattices

Yang Zhang·Noah F. Q. Yuan·Liang Fu
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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 work, by combining large-scale first principle calculation and continuum model approach, we provide an electronic structure theory that maps long-period heterobilayer TMD superlattices onto diatomic crystals with cations and anions. We find that the interplay between moiré potential and Coulomb interaction leads to filling-dependent charge transfer between MM and MX regions several nanometers apart. We show that the insulating state at half-filling found in recent experiments on WSe$_2$/WS$_2$ is a charge-transfer insulator rather than a Mott-Hubbard insulator. Our work reveals the richness of simplicity in moiré quantum chemistry.

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Yang Zhang, Noah F. Q. Yuan, Liang Fu. 2020-06-24. Moiré quantum chemistry: charge transfer in transition metal dichalcogenide superlattices. https://doi.org/10.1103/physrevb.102.201115

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