Title: Spectroscopy signatures of electron correlations in a trilayer graphene/hBN moiré superlattice

Abstract

ABC-stacked trilayer graphene/hexagonal boron nitride moiré superlattice (TLG/hBN) has emerged as a playground for correlated electron physics. Here, we report spectroscopy measurements of dual-gated TLG/hBN using Fourier transform infrared photocurrent spectroscopy. We observed a strong optical transition between moiré minibands that narrows continuously as a bandgap is opened by gating, indicating a reduction of the single-particle bandwidth. At half-filling of the valence flat band, a broad absorption peak emerges at ~18 milli–electron volts, indicating direct optical excitation across an emerging Mott gap. Similar photocurrent spectra are observed in two other correlated insulating states at quarter- and half-filling of the first conduction band. Our findings provide key parameters of the Hubbard model for the understanding of electron correlation in TLG/hBN.

Authors:

Yang, Jixiang  ^[1];

• Search DOE PAGES for author "Yang, Jixiang"
• Search DOE PAGES for ORCID "0000-0002-0392-2225"

Chen, Guorui  ^[2];

• Search DOE PAGES for author "Chen, Guorui"
• Search DOE PAGES for ORCID "0000-0002-4919-4796"

Han, Tianyi  ^[1];

• Search DOE PAGES for author "Han, Tianyi"
• Search DOE PAGES for ORCID "0000-0001-7767-0166"

Zhang, Qihang  ^[1];

• Search DOE PAGES for author "Zhang, Qihang"
• Search DOE PAGES for ORCID "0000-0001-5018-8310"

Zhang, Ya-Hui ^[3]; Jiang, Lili  ^[4];

• Search DOE PAGES for author "Jiang, Lili"
• Search DOE PAGES for ORCID "0000-0002-6930-4323"

Lyu, Bosai  ^[5];

• Search DOE PAGES for author "Lyu, Bosai"
• Search DOE PAGES for ORCID "0000-0001-8044-5509"

Li, Hongyuan ^[6]; Watanabe, Kenji  ^[7];

• Search DOE PAGES for author "Watanabe, Kenji"
• Search DOE PAGES for ORCID "0000-0003-3701-8119"

Taniguchi, Takashi  ^[7];

• Search DOE PAGES for author "Taniguchi, Takashi"
• Search DOE PAGES for ORCID "0000-0002-1467-3105"

Shi, Zhiwen  ^[5];

• Search DOE PAGES for author "Shi, Zhiwen"
• Search DOE PAGES for ORCID "0000-0002-3928-2960"

Senthil, Todadri  ^[1];

• Search DOE PAGES for author "Senthil, Todadri"
• Search DOE PAGES for ORCID "0000-0003-4203-4148"

Zhang, Yuanbo  ^[8];

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• Search DOE PAGES for ORCID "0000-0003-4745-8038"

Wang, Feng  ^[6];

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• Search DOE PAGES for ORCID "0000-0001-8369-6194"

Ju, Long  ^[1]

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• Search DOE PAGES for ORCID "0000-0002-4691-1315"

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+ Show Author Affiliations

1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
2. Shanghai Jiao Tong Univ. (China); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Univ. of California, Berkeley, CA (United States)
3. Harvard Univ., Cambridge, MA (United States)
4. Univ. of California, Berkeley, CA (United States)
5. Shanghai Jiao Tong Univ. (China)
6. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Science Division; Univ. of California, Berkeley, CA (United States)
7. National Institute for Materials Science (NIMS), Tsukuba (Japan)
8. Fudan Univ., Shanghai (China)

Publication Date:

Thu Mar 17 00:00:00 EDT 2022

Research Org.:

Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP); USDOE Office of Science (SC), Basic Energy Sciences (BES); National Key Research Program of China; National Natural Science Foundation of China (NSFC); Shanghai Jiao Tong University; Japan Society for the Promotion of Science (JSPS); Japan Ministry of Education, Culture, Sports, Science and Technology (MEXT); Japan Science and Technology Agency

OSTI Identifier:

1906097

Grant/Contract Number:  

AC02-05CH11231; SC0008739; DMR-1231319; 12174248; 11774224; 12074244; 2020YFA0309000; 2021YFA1400100; 21X010200846; JP20H00354; JPMXP0112101001; JPMJCR15F3

Resource Type:

Accepted Manuscript

Journal Name:

Science

Additional Journal Information:

Journal Volume: 375; Journal Issue: 6586; Journal ID: ISSN 0036-8075

Publisher:

AAAS

Country of Publication:

United States

Language:

English

Subject:

36 MATERIALS SCIENCE