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| Main Authors: | , , , , , , , , , , , , , , , , , , , , , , |
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| Format: | Preprint |
| Published: |
2022
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2208.02967 |
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| _version_ | 1866913467894595584 |
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| author | Rong, Hongtao Huang, Zhenqiao Zhang, Xin Kumar, Shiv Zhang, Fayuang Zhang, Chengcheng Wang, Yuan Hao, Zhanyang Cai, Yongqing Wang, Le Liu, Cai Ma, Xiao-Ming Guo, Shu Shen, Bing Liu, Yi Cui, Shengtao Shimada, Kenya Wu, Quansheng Lin, Junhao Yao, Yugui Wang, Zhiwei Xu, Hu Chen, Chaoyu |
| author_facet | Rong, Hongtao Huang, Zhenqiao Zhang, Xin Kumar, Shiv Zhang, Fayuang Zhang, Chengcheng Wang, Yuan Hao, Zhanyang Cai, Yongqing Wang, Le Liu, Cai Ma, Xiao-Ming Guo, Shu Shen, Bing Liu, Yi Cui, Shengtao Shimada, Kenya Wu, Quansheng Lin, Junhao Yao, Yugui Wang, Zhiwei Xu, Hu Chen, Chaoyu |
| contents | Space groups describing the symmetry of lattice structure allow the emergence of fermionic quasiparticles with various degeneracy in the band structure. Theoretical efforts have predicted many materials hosting fermions with the highest degeneracy, i.e., eightfold fermions, yet lacking experimental realization. Here, we explore the band degeneracies in TaCo$_2$Te$_2$ crystals. Through systematic experimental and theoretical analyses, we establish TaCo$_2$Te$_2$ as a nonsymmorphic crystal with negligible spin-orbit coupling (SOC) and long-range magnetic order. These critical properties guarantee the first realization of practical eightfold fermions and fourfold van Hove singularity, as directly observed by photoemission spectroscopy. TaCo$_2$Te$_2$ serves as a topological quantum critical platform, which can be tuned into various magnetic, topologically trivial, and nontrivial phases by adding strain, magnetic field, or SOC. The latter is demonstrated by our first-principles calculations, which show that enhancing SOC in TaCo$_2$Te$_2$ will promote the experimental observation of bulk hourglass fermions. Our results establish TaCo$_2$Te$_2$ as a unique platform to explore states of matter intertwining magnetism, correlation, symmetry, and band topology. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2208_02967 |
| institution | arXiv |
| publishDate | 2022 |
| record_format | arxiv |
| spellingShingle | Realization of Practical Eightfold Fermions and Fourfold van Hove Singularity in TaCo$_2$Te$_2$ Rong, Hongtao Huang, Zhenqiao Zhang, Xin Kumar, Shiv Zhang, Fayuang Zhang, Chengcheng Wang, Yuan Hao, Zhanyang Cai, Yongqing Wang, Le Liu, Cai Ma, Xiao-Ming Guo, Shu Shen, Bing Liu, Yi Cui, Shengtao Shimada, Kenya Wu, Quansheng Lin, Junhao Yao, Yugui Wang, Zhiwei Xu, Hu Chen, Chaoyu Strongly Correlated Electrons Space groups describing the symmetry of lattice structure allow the emergence of fermionic quasiparticles with various degeneracy in the band structure. Theoretical efforts have predicted many materials hosting fermions with the highest degeneracy, i.e., eightfold fermions, yet lacking experimental realization. Here, we explore the band degeneracies in TaCo$_2$Te$_2$ crystals. Through systematic experimental and theoretical analyses, we establish TaCo$_2$Te$_2$ as a nonsymmorphic crystal with negligible spin-orbit coupling (SOC) and long-range magnetic order. These critical properties guarantee the first realization of practical eightfold fermions and fourfold van Hove singularity, as directly observed by photoemission spectroscopy. TaCo$_2$Te$_2$ serves as a topological quantum critical platform, which can be tuned into various magnetic, topologically trivial, and nontrivial phases by adding strain, magnetic field, or SOC. The latter is demonstrated by our first-principles calculations, which show that enhancing SOC in TaCo$_2$Te$_2$ will promote the experimental observation of bulk hourglass fermions. Our results establish TaCo$_2$Te$_2$ as a unique platform to explore states of matter intertwining magnetism, correlation, symmetry, and band topology. |
| title | Realization of Practical Eightfold Fermions and Fourfold van Hove Singularity in TaCo$_2$Te$_2$ |
| topic | Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2208.02967 |