Liu Yi-Jun, Chen Yi-Wei, Zhu Yu-Jian, Huang Yan, An Dong-Dong, Li Qing-Xin, Gan Qi-Kang, Zhu Wang, Song Jun-Wei, Wang Kai-Yuan, Wei Ling-Nan, Zong Qi-Jun, Liu Shuo-Han, Li Shi-Wei, Liu Zhi, Zhang Qi, Xu Ying-Hai, Cao Xin-Yu, Yang Ao, Wang Hao-Lin, Yang Bing, Andy Shen, Yu Ge-Liang, Wang Lei
{"title":"双扭双层石墨烯中C=4的同位旋极化陈氏绝缘子态","authors":"Liu Yi-Jun, Chen Yi-Wei, Zhu Yu-Jian, Huang Yan, An Dong-Dong, Li Qing-Xin, Gan Qi-Kang, Zhu Wang, Song Jun-Wei, Wang Kai-Yuan, Wei Ling-Nan, Zong Qi-Jun, Liu Shuo-Han, Li Shi-Wei, Liu Zhi, Zhang Qi, Xu Ying-Hai, Cao Xin-Yu, Yang Ao, Wang Hao-Lin, Yang Bing, Andy Shen, Yu Ge-Liang, Wang Lei","doi":"10.7498/aps.72.20230497","DOIUrl":null,"url":null,"abstract":"Flat band with nearly zero dispersion can be engineered by twisting van der Waals materials relative to each other, and lead to a series of strongly correlated states, for example unconventional superconductivity, correlated insulating state, orbital magnetism. The bandwidth and topological property of electronic band structure in twisted double bilayer graphene is tunable by an external displacement field. This system could be an excellent quantum simulator to study the interplay between topological phase transition and strong electron correlation. Theoretical calculation shows that the broken of C2x symmetry in TDBG by an electric displacement field leads to finite Chern numbers at the lowest conduction and valence band near charge neutrality. Hence Chern insulator may emergent from this topological non-trivial flat band under strong electron interaction. Here, we observe Chern insulator state with Chern number 4 at filling factor v=1 under small magnetic fields on twisted double bilayer graphene with twist angle 1.48°. Moreover, the longitudinal resistance shows a peak under a parallel magnetic field and increases temperature and field, that is analogous to the Pomeranchuk effect in 3He. This phenomenon indicates that Chern insulator at v=1 may originate from isospin polarization.","PeriodicalId":6995,"journal":{"name":"物理学报","volume":"17 1","pages":""},"PeriodicalIF":0.8000,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Isospin polarized Chern insulator state of C=4 in twisted double bilayer graphene\",\"authors\":\"Liu Yi-Jun, Chen Yi-Wei, Zhu Yu-Jian, Huang Yan, An Dong-Dong, Li Qing-Xin, Gan Qi-Kang, Zhu Wang, Song Jun-Wei, Wang Kai-Yuan, Wei Ling-Nan, Zong Qi-Jun, Liu Shuo-Han, Li Shi-Wei, Liu Zhi, Zhang Qi, Xu Ying-Hai, Cao Xin-Yu, Yang Ao, Wang Hao-Lin, Yang Bing, Andy Shen, Yu Ge-Liang, Wang Lei\",\"doi\":\"10.7498/aps.72.20230497\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Flat band with nearly zero dispersion can be engineered by twisting van der Waals materials relative to each other, and lead to a series of strongly correlated states, for example unconventional superconductivity, correlated insulating state, orbital magnetism. The bandwidth and topological property of electronic band structure in twisted double bilayer graphene is tunable by an external displacement field. This system could be an excellent quantum simulator to study the interplay between topological phase transition and strong electron correlation. Theoretical calculation shows that the broken of C2x symmetry in TDBG by an electric displacement field leads to finite Chern numbers at the lowest conduction and valence band near charge neutrality. Hence Chern insulator may emergent from this topological non-trivial flat band under strong electron interaction. Here, we observe Chern insulator state with Chern number 4 at filling factor v=1 under small magnetic fields on twisted double bilayer graphene with twist angle 1.48°. Moreover, the longitudinal resistance shows a peak under a parallel magnetic field and increases temperature and field, that is analogous to the Pomeranchuk effect in 3He. This phenomenon indicates that Chern insulator at v=1 may originate from isospin polarization.\",\"PeriodicalId\":6995,\"journal\":{\"name\":\"物理学报\",\"volume\":\"17 1\",\"pages\":\"\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2023-01-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"物理学报\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.7498/aps.72.20230497\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"物理学报","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.7498/aps.72.20230497","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
Isospin polarized Chern insulator state of C=4 in twisted double bilayer graphene
Flat band with nearly zero dispersion can be engineered by twisting van der Waals materials relative to each other, and lead to a series of strongly correlated states, for example unconventional superconductivity, correlated insulating state, orbital magnetism. The bandwidth and topological property of electronic band structure in twisted double bilayer graphene is tunable by an external displacement field. This system could be an excellent quantum simulator to study the interplay between topological phase transition and strong electron correlation. Theoretical calculation shows that the broken of C2x symmetry in TDBG by an electric displacement field leads to finite Chern numbers at the lowest conduction and valence band near charge neutrality. Hence Chern insulator may emergent from this topological non-trivial flat band under strong electron interaction. Here, we observe Chern insulator state with Chern number 4 at filling factor v=1 under small magnetic fields on twisted double bilayer graphene with twist angle 1.48°. Moreover, the longitudinal resistance shows a peak under a parallel magnetic field and increases temperature and field, that is analogous to the Pomeranchuk effect in 3He. This phenomenon indicates that Chern insulator at v=1 may originate from isospin polarization.
期刊介绍:
Acta Physica Sinica (Acta Phys. Sin.) is supervised by Chinese Academy of Sciences and sponsored by Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. Published by Chinese Physical Society and launched in 1933, it is a semimonthly journal with about 40 articles per issue.
It publishes original and top quality research papers, rapid communications and reviews in all branches of physics in Chinese. Acta Phys. Sin. enjoys high reputation among Chinese physics journals and plays a key role in bridging China and rest of the world in physics research. Specific areas of interest include: Condensed matter and materials physics; Atomic, molecular, and optical physics; Statistical, nonlinear, and soft matter physics; Plasma physics; Interdisciplinary physics.