Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number
Studies of twisted moiré systems have been mainly focused on two-dimensional (2D) materials such as graphene with Dirac points and transition-metal dichalcogenides so far. Here we propose a twisted bilayer of 2D systems which feature stable quadratic-band-touching points and find exotic physics diff...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2022-11-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.4.043151 |
| _version_ | 1797210561358856192 |
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| author | Ming-Rui Li Ai-Lei He Hong Yao |
| author_facet | Ming-Rui Li Ai-Lei He Hong Yao |
| author_sort | Ming-Rui Li |
| collection | DOAJ |
| description | Studies of twisted moiré systems have been mainly focused on two-dimensional (2D) materials such as graphene with Dirac points and transition-metal dichalcogenides so far. Here we propose a twisted bilayer of 2D systems which feature stable quadratic-band-touching points and find exotic physics different from previously studied twisted moiré systems. Specifically, we show that exactly flat bands can emerge at magic angles and, more interestingly, each flat band exhibits a high Chern number (C=±2). We further consider the effect of Coulomb interactions in such magic-angle twisted systems and find that the ground state supports the quantum anomalous Hall effect with quantized Hall conductivity 2e^{2}/hc at certain filling. Furthermore, the possible physical realization of such twisted bilayer systems will be briefly discussed. |
| first_indexed | 2024-04-24T10:12:33Z |
| format | Article |
| id | doaj.art-213ff0258f1b4fb98e8aa06214b3edfb |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:12:33Z |
| publishDate | 2022-11-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-213ff0258f1b4fb98e8aa06214b3edfb2024-04-12T17:26:37ZengAmerican Physical SocietyPhysical Review Research2643-15642022-11-014404315110.1103/PhysRevResearch.4.043151Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern numberMing-Rui LiAi-Lei HeHong YaoStudies of twisted moiré systems have been mainly focused on two-dimensional (2D) materials such as graphene with Dirac points and transition-metal dichalcogenides so far. Here we propose a twisted bilayer of 2D systems which feature stable quadratic-band-touching points and find exotic physics different from previously studied twisted moiré systems. Specifically, we show that exactly flat bands can emerge at magic angles and, more interestingly, each flat band exhibits a high Chern number (C=±2). We further consider the effect of Coulomb interactions in such magic-angle twisted systems and find that the ground state supports the quantum anomalous Hall effect with quantized Hall conductivity 2e^{2}/hc at certain filling. Furthermore, the possible physical realization of such twisted bilayer systems will be briefly discussed.http://doi.org/10.1103/PhysRevResearch.4.043151 |
| spellingShingle | Ming-Rui Li Ai-Lei He Hong Yao Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number Physical Review Research |
| title | Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number |
| title_full | Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number |
| title_fullStr | Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number |
| title_full_unstemmed | Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number |
| title_short | Magic-angle twisted bilayer systems with quadratic band touching: Exactly flat bands with high Chern number |
| title_sort | magic angle twisted bilayer systems with quadratic band touching exactly flat bands with high chern number |
| url | http://doi.org/10.1103/PhysRevResearch.4.043151 |
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