Imaging moiré flat bands in three-dimensional reconstructed WSe2/WS2 superlattices

Moiré superlattices in transition metal dichalcogenide (TMD) heterostructures can host novel correlated quantum phenomena due to the interplay of narrow moiré flat bands and strong, long-range Coulomb interactions 1 – 9 . However, microscopic knowledge of the atomically reconstructed moiré superlatt...

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Vydáno v:Nature materials Ročník 20; číslo 7; s. 945 - 950
Hlavní autoři: Li, Hongyuan, Li, Shaowei, Naik, Mit H., Xie, Jingxu, Li, Xinyu, Wang, Jiayin, Regan, Emma, Wang, Danqing, Zhao, Wenyu, Zhao, Sihan, Kahn, Salman, Yumigeta, Kentaro, Blei, Mark, Taniguchi, Takashi, Watanabe, Kenji, Tongay, Sefaattin, Zettl, Alex, Louie, Steven G., Wang, Feng, Crommie, Michael F.
Médium: Journal Article
Jazyk:angličtina
Vydáno: London Nature Publishing Group UK 01.07.2021
Nature Publishing Group
Springer Nature - Nature Publishing Group
Témata:
639/301/119/1002
639/301/119/995
639/766/119/1000/1018
639/766/930/2735
Biomaterials
Brillouin zones
Buckling
Chemistry and Materials Science
Condensed Matter Physics
Electronic properties and materials
Heterostructures
Image reconstruction
Imaging techniques
Letter
MATERIALS SCIENCE
Nanotechnology
Optical and Electronic Materials
Plane strain
Quantum phenomena
Scanning
Scanning tunneling microscopy
Simulation
Spectroscopy
Spectrum analysis
Structure of solids and liquids
Superlattices
Transition metal compounds
Tungsten disulfide
Two-dimensional materials
Valence band
ISSN:1476-1122, 1476-4660, 1476-4660
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Popis
Shrnutí:Moiré superlattices in transition metal dichalcogenide (TMD) heterostructures can host novel correlated quantum phenomena due to the interplay of narrow moiré flat bands and strong, long-range Coulomb interactions 1 – 9 . However, microscopic knowledge of the atomically reconstructed moiré superlattice and resulting flat bands is still lacking, which is critical for fundamental understanding and control of the correlated moiré phenomena. Here we quantitatively study the moiré flat bands in three-dimensional (3D) reconstructed WSe 2 /WS 2 moiré superlattices by comparing scanning tunnelling spectroscopy (STS) of high-quality exfoliated TMD heterostructure devices with ab initio simulations of TMD moiré superlattices. A strong 3D buckling reconstruction accompanied by large in-plane strain redistribution is identified in our WSe 2 /WS 2 moiré heterostructures. STS imaging demonstrates that this results in a remarkably narrow and highly localized K-point moiré flat band at the valence band edge of the heterostructure. A series of moiré flat bands are observed at different energies that exhibit varying degrees of localization. Our observations contradict previous simplified theoretical models but agree quantitatively with ab initio simulations that fully capture the 3D structural reconstruction. Our results reveal that the strain redistribution and 3D buckling in TMD heterostructures dominate the effective moiré potential and the corresponding moiré flat bands at the Brillouin zone K points. Scanning tunnelling spectroscopy and ab initio simulations reveal buckling reconstruction and in-plane strain redistribution in WSe 2 /WS 2 moiré heterostructures.
Bibliografie:ObjectType-Article-1
SourceType-Scholarly Journals-1
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AC02-05CH11231; SC0020653; ACI-1053575; OAC-1818253
National Science Foundation (NSF)
Directorate for Mathematical & Physical Sciences
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
ISSN:1476-1122
1476-4660
1476-4660
DOI:10.1038/s41563-021-00923-6