Kim, Youngwook Park, Jaesung Song, Intek Ok, Jong Mok Jo, Younjung Watanabe, Kenji Taniquchi, Takashi Choi, Hee Cheul Lee, Dong Su Jung, Suyong Kim, Jun Sung 2024-01-20T02:33:59Z 2024-01-20T02:33:59Z 2021-08-31 2016-12-01 2045-2322 https://pubs.kist.re.kr/handle/201004/123334 Twisted bilayer graphene offers a unique bilayer two-dimensional-electron system where the layer separation is only in sub-nanometer scale. Unlike Bernal-stacked bilayer, the layer degree of freedom is disentangled from spin and valley, providing eight-fold degeneracy in the low energy states. We have investigated broken-symmetry quantum Hall (QH) states and their transitions due to the interplay of the relative strength of valley, spin and layer polarizations in twisted bilayer graphene. The energy gaps of the broken-symmetry QH states show an electron-hole asymmetric behaviour, and their dependence on the induced displacement field are opposite between even and odd filling factor states. These results strongly suggest that the QH states with broken valley and spin symmetries for individual layer become hybridized via interlayer tunnelling, and the hierarchy of the QH states is sensitive to both magnetic field and displacement field due to charge imbalance between layers. English NATURE PUBLISHING GROUP ELECTRON-SYSTEMS PHASE-TRANSITION FERROMAGNETISM SPIN WELL Broken-Symmetry Quantum Hall States in Twisted Bilayer Graphene Article 10.1038/srep38068 1 SCIENTIFIC REPORTS, v.6 SCIENTIFIC REPORTS 6 scie scopus 000389657500001 Multidisciplinary Sciences Science & Technology - Other Topics Article ELECTRON-SYSTEMS PHASE-TRANSITION FERROMAGNETISM SPIN WELL quantum Hall effect graphene twisted bilayer graphene broken-symmetry