This took us a Weyl: synthesis of a semimetallic Weyl ferromagnet with point Fermi surface
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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| _version_ | 1866909379351019520 |
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| author | Belopolski, Ilya Watanabe, Ryota Sato, Yuki Yoshimi, Ryutaro Kawamura, Minoru Nagahama, Soma Zhao, Yilin Shao, Sen Jin, Yuanjun Kato, Yoshihiro Okamura, Yoshihiro Zhang, Xiao-Xiao Fujishiro, Yukako Takahashi, Youtarou Hirschberger, Max Tsukazaki, Atsushi Takahashi, Kei S. Chiu, Ching-Kai Chang, Guoqing Kawasaki, Masashi Nagaosa, Naoto Tokura, Yoshinori |
| author_facet | Belopolski, Ilya Watanabe, Ryota Sato, Yuki Yoshimi, Ryutaro Kawamura, Minoru Nagahama, Soma Zhao, Yilin Shao, Sen Jin, Yuanjun Kato, Yoshihiro Okamura, Yoshihiro Zhang, Xiao-Xiao Fujishiro, Yukako Takahashi, Youtarou Hirschberger, Max Tsukazaki, Atsushi Takahashi, Kei S. Chiu, Ching-Kai Chang, Guoqing Kawasaki, Masashi Nagaosa, Naoto Tokura, Yoshinori |
| contents | Quantum materials governed by emergent topological fermions have become a cornerstone of physics. Dirac fermions in graphene form the basis for moiré quantum matter, and Dirac fermions in magnetic topological insulators enabled the discovery of the quantum anomalous Hall effect. In contrast, there are few materials whose electromagnetic response is dominated by emergent Weyl fermions. Nearly all known Weyl materials are overwhelmingly metallic, and are largely governed by irrelevant, conventional electrons. Here we theoretically predict and experimentally observe a semimetallic Weyl ferromagnet in van der Waals (Cr,Bi)$_2$Te$_3$. In transport, we find a record bulk anomalous Hall angle $> 0.5$ along with non-metallic conductivity, a regime sharply distinct from conventional ferromagnets. Together with symmetry analysis, our data suggest a semimetallic Fermi surface composed of two Weyl points, with a giant separation $> 75\%$ of the linear dimension of the bulk Brillouin zone, and no other electronic states. Using state-of-the-art crystal synthesis techniques, we widely tune the electronic structure, allowing us to annihilate the Weyl state and visualize a unique topological phase diagram exhibiting broad Chern insulating, Weyl semimetallic and magnetic semiconducting regions. Our observation of a semimetallic Weyl ferromagnet offers an avenue toward novel correlated states and non-linear phenomena, as well as zero-magnetic-field Weyl spintronic and optical devices. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2411_04179 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | This took us a Weyl: synthesis of a semimetallic Weyl ferromagnet with point Fermi surface Belopolski, Ilya Watanabe, Ryota Sato, Yuki Yoshimi, Ryutaro Kawamura, Minoru Nagahama, Soma Zhao, Yilin Shao, Sen Jin, Yuanjun Kato, Yoshihiro Okamura, Yoshihiro Zhang, Xiao-Xiao Fujishiro, Yukako Takahashi, Youtarou Hirschberger, Max Tsukazaki, Atsushi Takahashi, Kei S. Chiu, Ching-Kai Chang, Guoqing Kawasaki, Masashi Nagaosa, Naoto Tokura, Yoshinori Mesoscale and Nanoscale Physics Materials Science Quantum materials governed by emergent topological fermions have become a cornerstone of physics. Dirac fermions in graphene form the basis for moiré quantum matter, and Dirac fermions in magnetic topological insulators enabled the discovery of the quantum anomalous Hall effect. In contrast, there are few materials whose electromagnetic response is dominated by emergent Weyl fermions. Nearly all known Weyl materials are overwhelmingly metallic, and are largely governed by irrelevant, conventional electrons. Here we theoretically predict and experimentally observe a semimetallic Weyl ferromagnet in van der Waals (Cr,Bi)$_2$Te$_3$. In transport, we find a record bulk anomalous Hall angle $> 0.5$ along with non-metallic conductivity, a regime sharply distinct from conventional ferromagnets. Together with symmetry analysis, our data suggest a semimetallic Fermi surface composed of two Weyl points, with a giant separation $> 75\%$ of the linear dimension of the bulk Brillouin zone, and no other electronic states. Using state-of-the-art crystal synthesis techniques, we widely tune the electronic structure, allowing us to annihilate the Weyl state and visualize a unique topological phase diagram exhibiting broad Chern insulating, Weyl semimetallic and magnetic semiconducting regions. Our observation of a semimetallic Weyl ferromagnet offers an avenue toward novel correlated states and non-linear phenomena, as well as zero-magnetic-field Weyl spintronic and optical devices. |
| title | This took us a Weyl: synthesis of a semimetallic Weyl ferromagnet with point Fermi surface |
| topic | Mesoscale and Nanoscale Physics Materials Science |
| url | https://arxiv.org/abs/2411.04179 |