# Observation of First-Order Quantum Phase Transitions and Ferromagnetism in Twisted Double Bilayer Graphene https://mdr.nims.go.jp/datasets/666beb2a-389d-43e1-8266-0f86e7dcfe8d ## File - [PhysRevX.13.031015-2.pdf](https://mdr.nims.go.jp/filesets/19ccadbe-3e6d-48b2-b82f-a6a1d1b4ddc3/download) ([Detail](https://mdr.nims.go.jp/filesets/19ccadbe-3e6d-48b2-b82f-a6a1d1b4ddc3.md)) ## Id 666beb2a-389d-43e1-8266-0f86e7dcfe8d ## Local identifier ## Visibility open_to_public ## State published ## Created at 2025-02-27T07:24:11.113266Z ## Updated at 2025-02-28T07:30:34.285343Z ## Published at 2025-02-28T07:30:34.393297Z ## Doi ## First published url https://doi.org/10.1103/physrevx.13.031015 ## Date published 2023-08-07 ## Recorded date published 2023-8 ## Resource type journal_article ## Manuscript type vor ## Collection ## Title - title: Observation of First-Order Quantum Phase Transitions and Ferromagnetism in Twisted Double Bilayer Graphene title_type: original lang: en ## Description - description: Twisted graphene multilayers are highly tunable flatband systems for developing new phases of matter. Here, we report an observation of Coulomb interaction driven first-order phase transitions and ferromagnetism in twisted double bilayer graphene (TDBG). The transitions are revealed in a series of step-like abrupt resistance jumps at the metal insulator transition due to van Hove instabilities when either the displacement field (D) or the carrier density (n) is swept across the halo boundary near the half filling. Consequently, prominent hysteresis loop appears as the D or n is tuned back and forth across the transition, indicating a formation of ordered domain. In addition, ferromagnetic first-order transitions with hysteresis are also observed at the magnetic field driven metal insulator transitions, where the nature of spin order is revealed in the identical magneto transport under both in-plane and out-of-plane directions. Moreover, we observe abundant first-order phase transitions between metal with preserved 4-fold symmetry and ferromagnetic metal with reduced 2- fold symmetry due to valley polarization, as well as the those between ferromagnetic metal and spin- polarized insulator, resulted from a competition between spin and orbital Zeeman effect at finite magnetic field. We interpret these first-order phase transitions in the picture of spin domain percolations driven by multi-field tunable Coulomb interactions, in agreement with Lifshitz transition from Hartree-Fock calculations. Our result enriches the correlated phase diagram in TDBG for discovering novel exotic phases and quantum phase transitions, and it would benefit other twisted moiré systems as well. description_type: abstract lang: und ## Creator - name: Le Liu role: author - name: Xin Lu role: author - name: Yanbang Chu role: author - name: Guang Yang role: author - name: Yalong Yuan role: author - name: Fanfan Wu role: author - name: Yiru Ji role: author - name: Jinpeng Tian role: author - name: Kenji Watanabe role: author orcid: https://orcid.org/0000-0003-3701-8119 organization: National Institute for Materials Science ror: https://ror.org/026v1ze26 - name: Takashi Taniguchi role: author orcid: https://orcid.org/0000-0002-1467-3105 organization: National Institute for Materials Science ror: https://ror.org/026v1ze26 - name: Luojun Du role: author - name: Dongxia Shi role: author - name: Jianpeng Liu role: author - name: Jie Shen role: author - name: Li Lu role: author - name: Wei Yang role: author - name: Guangyu Zhang role: author ## Contact agent ## Publisher organization: American Physical Society (APS) ## Managing organization ## Keyword - subject: Twisted graphene schema: not_defined - subject: quantum phase transitions schema: not_defined - subject: ferromagnetism schema: not_defined ## Rights - identifier: https://creativecommons.org/licenses/by/4.0/ ## Other identifier(s) ## Data origin - data_origin_type: other ## Embargo ## Journal - title: Physical Review X issn: '21603308' volume: '13' issue: '3' article_number: '031015' ## Conference ## Related item ## Funding - identifier: 2020YFA0309600 funder_name: National Key Research and Development Program of China - identifier: 2021YFA1202900 funder_name: National Key Research and Development Program of China - identifier: '61888102' funder_name: National Natural Science Foundation of China - identifier: '11834017' funder_name: National Natural Science Foundation of China - identifier: '12074413' funder_name: National Natural Science Foundation of China - identifier: XDB30000000 funder_name: Chinese Academy of Sciences - identifier: XDB33000000 funder_name: Chinese Academy of Sciences - identifier: 2020B0101340001 funder_name: Special Project for Research and Development in Key areas of Guangdong Province - funder_name: Institute of Physics - identifier: JPMXP0112101001 funder_name: Ministry of Education, Culture, Sports, Science and Technology - identifier: 19H05790 funder_name: Japan Society for the Promotion of Science - identifier: 20H00354 funder_name: Japan Society for the Promotion of Science - identifier: 21H05233 funder_name: Japan Society for the Promotion of Science ## Instrument ## Instrument operator ## Instrument managing organization ## Measurement method ## Specimen ## Chemical composition ## Structure for specimen ## Structural feature for specimen ## Specific property for specimen ## Process for specimen treatment ## Computational method ## Energy level/transition state ## Software ## Custom property ## Fileset - id: 19ccadbe-3e6d-48b2-b82f-a6a1d1b4ddc3 filename: PhysRevX.13.031015-2.pdf content_type: application/pdf size: 1808676 md5: 65f59e15374d7d87dbb411a96370083d ## Thumbnail fileset_id: 19ccadbe-3e6d-48b2-b82f-a6a1d1b4ddc3 filename: PhysRevX.13.031015-2.pdf