Link between cascade transitions and correlated Chern insulators in magic-angle twisted bilayer graphene
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| Main Authors: | , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866914833572560896 |
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| author | Hu, Qianying Liang, Shu Li, Xinheng Shi, Hao Dai, Xi Xu, Yang |
| author_facet | Hu, Qianying Liang, Shu Li, Xinheng Shi, Hao Dai, Xi Xu, Yang |
| contents | Chern insulators are topologically non-trivial states of matter characterized by incompressible bulk and chiral edge states. Incorporating topological Chern bands with strong electronic correlations provides a versatile playground for studying emergent quantum phenomena. In this study, we resolve the correlated Chern insulators (CCIs) in magic-angle twisted bilayer graphene (MATBG) through Rydberg exciton sensing spectroscopy, and unveil their direct link with the zero-field cascade features in the electronic compressibility. The compressibility minima in the cascade are found to deviate substantially from nearby integer fillings (by $Δν$) and coincide with the onsets of CCIs in doping densities, yielding a quasi-universal relation $B_c$=$Φ_0Δν/C$ (onset magnetic field $B_c$, magnetic flux quantum $Φ_0$ and Chern number $C$). We suggest these onsets lie on the intersection where the integer filling of localized "f-orbitals" and Chern bands are simultaneously reached. Our findings update the field-dependent phase diagram of MATBG and directly support the topological heavy fermion model. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2406_08734 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Link between cascade transitions and correlated Chern insulators in magic-angle twisted bilayer graphene Hu, Qianying Liang, Shu Li, Xinheng Shi, Hao Dai, Xi Xu, Yang Mesoscale and Nanoscale Physics Strongly Correlated Electrons Chern insulators are topologically non-trivial states of matter characterized by incompressible bulk and chiral edge states. Incorporating topological Chern bands with strong electronic correlations provides a versatile playground for studying emergent quantum phenomena. In this study, we resolve the correlated Chern insulators (CCIs) in magic-angle twisted bilayer graphene (MATBG) through Rydberg exciton sensing spectroscopy, and unveil their direct link with the zero-field cascade features in the electronic compressibility. The compressibility minima in the cascade are found to deviate substantially from nearby integer fillings (by $Δν$) and coincide with the onsets of CCIs in doping densities, yielding a quasi-universal relation $B_c$=$Φ_0Δν/C$ (onset magnetic field $B_c$, magnetic flux quantum $Φ_0$ and Chern number $C$). We suggest these onsets lie on the intersection where the integer filling of localized "f-orbitals" and Chern bands are simultaneously reached. Our findings update the field-dependent phase diagram of MATBG and directly support the topological heavy fermion model. |
| title | Link between cascade transitions and correlated Chern insulators in magic-angle twisted bilayer graphene |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2406.08734 |