Electron-hole hybridization in bilayer graphene

Journal Article · 19 December 2019 · National Science Review

DOI: https://doi.org/10.1093/nsr/nwz212 · OSTI ID:2469656

Wang, Siqi ^[1]; Zhao, Mervin ^[1]; Zhang, Changjian ^[2]; Yang, Sui ^[1]; Wang, Yuan ^[1]; Watanabe, Kenji ^[3]; Taniguchi, Takashi ^[3]; Hone, James ^[2]; Zhang, Xiang ^[4]

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1. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2. Columbia Univ., New York, NY (United States)
3. National Institute for Materials Science (NIMS), Tsukuba (Japan)
4. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Univ. of Hong Kong (China)

Band structure determines the motion of electrons in a solid, giving rise to exotic phenomena when properly engineered. Drawing an analogy between electrons and photons, artificially designed optical lattices indicate the possibility of a similar band modulation effect in graphene systems. Yet due to the fermionic nature of electrons, modulated electronic systems promise far richer categories of behaviors than those found in optical lattices. Here, we uncovered a strong modulation of electronic states in bilayer graphene subject to periodic potentials. We observed for the first time the hybridization of electron and hole sub-bands, resulting in local band gaps at both primary and secondary charge neutrality points. Such hybridization leads to the formation of flat bands, enabling the study of correlated effects in graphene systems. This work may provide a novel way to manipulate electronic states in layered systems, which is important to both fundamental research and application.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 2469656
• Journal Information: National Science Review, Journal Name: National Science Review Journal Issue: 2 Vol. 7; ISSN 2095-5138
• Publisher: China Science PublishingCopyright Statement
• Country of Publication: United States
• Language: English