Observation of High-Temperature Dissipationless Fractional Chern Insulator
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2025
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| author | Park, Heonjoon Li, Weijie Hu, Chaowei Beach, Christiano Gonçalves, Miguel Mendez-Valderrama, Juan Felipe Herzog-Arbeitman, Jonah Taniguchi, Takashi Watanabe, Kenji Cobden, David Fu, Liang Bernevig, B. Andrei Regnault, Nicolas Chu, Jiun-Haw Xiao, Di Xu, Xiaodong |
| author_facet | Park, Heonjoon Li, Weijie Hu, Chaowei Beach, Christiano Gonçalves, Miguel Mendez-Valderrama, Juan Felipe Herzog-Arbeitman, Jonah Taniguchi, Takashi Watanabe, Kenji Cobden, David Fu, Liang Bernevig, B. Andrei Regnault, Nicolas Chu, Jiun-Haw Xiao, Di Xu, Xiaodong |
| contents | The fractional quantum anomalous Hall effect has recently been experimentally observed in zero-field fractional Chern insulators (FCI). However, an outstanding challenge is the presence of a substantial longitudinal resistance $R_{xx}$ (a few k$Ω$), even though the anomalous Hall resistance $R_{xy}$ is quantized. This dissipative behavior is likely linked to imperfect sample quality. Here, we report transport measurements of a drastically improved twisted $\text{MoTe}_2$ bilayer device, which exhibits quantized $R_{xy}$ and vanishing $R_{xx}$ for the $-2/3$ state, marking a dissipationless FCI. Contrary to fractional quantum Hall states where the energy gap increases with magnetic field, we find that the thermal activation gap of the observed FCI states decreases rapidly as the magnetic field rises from zero, then plateaus above a few teslas. This observation is attributed to the interplay between spin and charge gaps. Due to the spontaneous ferromagnetism, the spin gap dominates at low field, while the charge gap becomes appreciable once the magnetic field freezes spin fluctuations. For the $-2/3$ state, we estimate the spin and FCI gap of about 55 and 20 K, respectively. Our results provide insights into the energy scale of FCI and offer a pathway for quantum engineering of exotic correlated topological states. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_10989 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Observation of High-Temperature Dissipationless Fractional Chern Insulator Park, Heonjoon Li, Weijie Hu, Chaowei Beach, Christiano Gonçalves, Miguel Mendez-Valderrama, Juan Felipe Herzog-Arbeitman, Jonah Taniguchi, Takashi Watanabe, Kenji Cobden, David Fu, Liang Bernevig, B. Andrei Regnault, Nicolas Chu, Jiun-Haw Xiao, Di Xu, Xiaodong Mesoscale and Nanoscale Physics Strongly Correlated Electrons The fractional quantum anomalous Hall effect has recently been experimentally observed in zero-field fractional Chern insulators (FCI). However, an outstanding challenge is the presence of a substantial longitudinal resistance $R_{xx}$ (a few k$Ω$), even though the anomalous Hall resistance $R_{xy}$ is quantized. This dissipative behavior is likely linked to imperfect sample quality. Here, we report transport measurements of a drastically improved twisted $\text{MoTe}_2$ bilayer device, which exhibits quantized $R_{xy}$ and vanishing $R_{xx}$ for the $-2/3$ state, marking a dissipationless FCI. Contrary to fractional quantum Hall states where the energy gap increases with magnetic field, we find that the thermal activation gap of the observed FCI states decreases rapidly as the magnetic field rises from zero, then plateaus above a few teslas. This observation is attributed to the interplay between spin and charge gaps. Due to the spontaneous ferromagnetism, the spin gap dominates at low field, while the charge gap becomes appreciable once the magnetic field freezes spin fluctuations. For the $-2/3$ state, we estimate the spin and FCI gap of about 55 and 20 K, respectively. Our results provide insights into the energy scale of FCI and offer a pathway for quantum engineering of exotic correlated topological states. |
| title | Observation of High-Temperature Dissipationless Fractional Chern Insulator |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2503.10989 |