Realization of practical eightfold fermions and fourfold van Hove singularity in TaCo2Te2

Rong，Hongtao1; Huang，Zhenqiao1,2; Zhang，Xin3,4; Kumar，Shiv5; Zhang，Fayuang1; Zhang，Chengcheng1; Wang，Yuan1; Hao，Zhanyang1; Cai，Yongqing1; Wang，Le1; Liu，Cai1; Ma，Xiaoming1; Guo，Shu1; Shen，Bing6; Liu，Yi7; Cui，Shengtao7; Shimada，Kenya5; Wu，Quansheng8,9; Lin，Junhao1; Yao，Yugui3,4; Wang，Zhiwei3,4,10; Xu，Hu1; Chen，Chaoyu1

2023-12-01

10.1038/s41535-023-00565-8

npj Quantum Materials   Impact Factor & Quartile

2397-4648

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 TaCoTe crystals. Through systematic experimental and theoretical analyses, we establish TaCoTe as a nonsymmorphic crystal with negligible spin–orbit coupling (SOC) and long-range magnetic order. These critical properties guarantee the realization of practical eightfold fermions and fourfold van Hove singularity, as directly observed by photoemission spectroscopy. TaCoTe 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 TaCoTe will promote the experimental observation of bulk hourglass fermions. Our results establish TaCoTe as a platform to explore the interplay between symmetry and band topology.

SCI

English

First ; Corresponding

National Natural Science Foundation of China-Yunnan Joint Fund[12074163];

Materials Science ; Physics

Materials Science, Multidisciplinary ; Quantum Science & Technology ; Physics, Applied ; Physics, Condensed Matter

WOS:000998423800001

NATURE PORTFOLIO

2-s2.0-85160611669

Scopus

1.Shenzhen Institute for Quantum Science and Engineering (SIQSE) and Department of Physics,Southern University of Science and Technology (SUSTech),Shenzhen,518055,China
2.Department of Physics,The Hong Kong University of Science and Technology,Clear Water Bay,Hong Kong
3.Centre for Quantum Physics,Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement,School of Physics,Beijing Institute of Technology,Beijing,100081,China
4.Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems,Beijing Institute of Technology,Beijing,10008,China
5.Hiroshima Synchrotron Radiation Centre,Hiroshima University,Higashi-Hiroshima,Hiroshima,739-0046,Japan
6.School of Physics,Sun Yat-Sen University,Guangzhou,510275,China
7.National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei,Anhui,230029,China
8.Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing,100190,China
9.University of Chinese Academy of Sciences,Beijing,100049,China
10.Material Science Center,Yangtze Delta Region Academy of Beijing Institute of Technology,Jiaxing,314011,China

Rong，Hongtao,Huang，Zhenqiao,Zhang，Xin,et al. Realization of practical eightfold fermions and fourfold van Hove singularity in TaCo2Te2[J]. npj Quantum Materials,2023,8(1).

Rong，Hongtao.,Huang，Zhenqiao.,Zhang，Xin.,Kumar，Shiv.,Zhang，Fayuang.,...&Chen，Chaoyu.(2023).Realization of practical eightfold fermions and fourfold van Hove singularity in TaCo2Te2.npj Quantum Materials,8(1).

Rong，Hongtao,et al."Realization of practical eightfold fermions and fourfold van Hove singularity in TaCo2Te2".npj Quantum Materials 8.1(2023).