Evidence of a gate-tunable mott insulator in a trilayer graphene moiré superlattice

ABSTRACT The Mott insulator is a central concept in strongly correlated physics and manifests when the repulsive Coulomb interaction between electrons dominates over their kinetic energy1,2.

Doping additional carriers into a Mott insulator can give rise to other correlated phenomena such as unusual magnetism and even high-temperature superconductivity2,3. A tunable Mott

insulator, where the competition between the Coulomb interaction and the kinetic energy can be varied in situ, can provide an invaluable model system for the study of Mott physics. Here we

report the possible realization of such a tunable Mott insulator in a trilayer graphene heterostructure with a moiré superlattice. The combination of the cubic energy dispersion in

ABC-stacked trilayer graphene4,5,6,7,8 and the narrow electronic minibands induced by the moiré potential9,10,11,12,13,14,15 leads to the observation of insulating states at the predicted

band fillings for the Mott insulator. Moreover, the insulating states in the heterostructure can be tuned: the bandgap can be modulated by a vertical electrical field, and at the same time

the electron doping can be modified by a gate to fill the band from one insulating state to another. This opens up exciting opportunities to explore strongly correlated phenomena in

two-dimensional moiré superlattice heterostructures. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS OPTIONS

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Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS TUNABLE STRONGLY COUPLED SUPERCONDUCTIVITY IN MAGIC-ANGLE TWISTED TRILAYER GRAPHENE Article 01 February 2021 EVIDENCE FOR

UNCONVENTIONAL SUPERCONDUCTIVITY IN TWISTED TRILAYER GRAPHENE Article 15 June 2022 GATE-TUNABLE HEAVY FERMIONS IN A MOIRÉ KONDO LATTICE Article 15 March 2023 DATA AVAILABILITY The data that

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Regan, X. Lu, Y. Shan, S. Wu and G. Zhang for discussions and help with sample preparation. The trilayer graphene sample fabrication and experimental study was supported by the Office of

Naval Research (award no. N00014-15-1-2651). The initial idea and proof-of-principle calculation of 2D flatband engineering was supported by an ARO MURI award (W911NF-15-1-0447). Part of the

sample fabrication was conducted at the Nano-fabrication Laboratory at Fudan University. B.L.C. was supported by the Basic Science Research Program through the National Research Foundation

of Korea (NRF) funded by the Ministry of Education (2018R1A6A1A06024977) and by grants NRF-2016R1A2B4010105 and NRF-2017R1D1A1B03035932. J.J. was supported by the Samsung Science and

Technology Foundation under project no. SSTF-BA1802-06. Y.Z. acknowledges financial support from the National Key Research Program of China (grant nos. 2016YFA0300703 and 2018YFA0305600),

the NSF of China (grant nos. U1732274, 11527805, 11425415 and 11421404), Shanghai Municipal Science and Technology Commission (grant no. 18JC1410300) and the Strategic Priority Research

Program of the Chinese Academy of Sciences (grant no. XDB30000000). Z.S. is supported by the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher

Learning and the National Natural Science Foundation of China under grant no. 11574204. B.L., H.L. and Z.S. are supported by the National Key Research and Development Program of China

(grant 2016YFA0302001) and National Natural Science Foundation of China (grants 11574204, 11774224). Growth of hBN crystals was supported by the Elemental Strategy Initiative conducted by

the MEXT, Japan and JSPS KAKENHI grant no. JP15K21722. Part of the sample fabrication was conducted at Fudan Nano-fabrication Lab. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of

Physics, University of California at Berkeley, Berkeley, CA, USA Guorui Chen, Lili Jiang & Feng Wang * State Key Laboratory of Surface Physics and Department of Physics, Fudan

University, Shanghai, China Guorui Chen & Yuanbo Zhang * Collaborative Innovation Center of Advanced Microstructures, Nanjing, China Guorui Chen, Bosai Lyu, Hongyuan Li, Zhiwen Shi &

 Yuanbo Zhang * Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA Shuang Wu * Key Laboratory of Artificial Structures and Quantum

Control (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai, China Bosai Lyu, Hongyuan Li & Zhiwen Shi * Department of Physics, University

of Seoul, Seoul, Korea Bheema Lingam Chittari & Jeil Jung * National Institute for Materials Science, Tsukuba, Japan Kenji Watanabe & Takashi Taniguchi * Institute for Nanoelectronic

Devices and Quantum Computing, Fudan University, Shanghai, China Yuanbo Zhang * Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA Feng Wang * Kavli Energy

NanoSciences Institute at the University of California, Berkeley and the Lawrence Berkeley National Laboratory, Berkeley, CA, USA Feng Wang Authors * Guorui Chen View author publications

You can also search for this author inPubMed Google Scholar * Lili Jiang View author publications You can also search for this author inPubMed Google Scholar * Shuang Wu View author

publications You can also search for this author inPubMed Google Scholar * Bosai Lyu View author publications You can also search for this author inPubMed Google Scholar * Hongyuan Li View

author publications You can also search for this author inPubMed Google Scholar * Bheema Lingam Chittari View author publications You can also search for this author inPubMed Google Scholar

* Kenji Watanabe View author publications You can also search for this author inPubMed Google Scholar * Takashi Taniguchi View author publications You can also search for this author

inPubMed Google Scholar * Zhiwen Shi View author publications You can also search for this author inPubMed Google Scholar * Jeil Jung View author publications You can also search for this

author inPubMed Google Scholar * Yuanbo Zhang View author publications You can also search for this author inPubMed Google Scholar * Feng Wang View author publications You can also search

for this author inPubMed Google Scholar CONTRIBUTIONS F.W. and Y.Z. supervised the project. G.C. fabricated samples and performed transport measurements. G.C., L.J., S.W., B.L., H.L. and

Z.S. prepared trilayer graphene and performed near-field infrared and atomic force microscopy measurements. B.L.C. and J.J. calculated the band structures. K.W. and T.T. grew hBN single

crystals. G.C., Y.Z. and F.W. analysed the data. CORRESPONDING AUTHORS Correspondence to Yuanbo Zhang or Feng Wang. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing

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INFORMATION EXTENDED DATA Extended data figures 1–7; references 30–35 RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Chen, G., Jiang, L., Wu, S. _et

al._ Evidence of a gate-tunable Mott insulator in a trilayer graphene moiré superlattice. _Nat. Phys._ 15, 237–241 (2019). https://doi.org/10.1038/s41567-018-0387-2 Download citation *

Received: 01 November 2018 * Accepted: 27 November 2018 * Published: 21 January 2019 * Issue Date: March 2019 * DOI: https://doi.org/10.1038/s41567-018-0387-2 SHARE THIS ARTICLE Anyone you

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