The discovery of three-dimensional Van Hove singularity

Wenbin Wu; Zeping Shi; Mykhaylo Ozerov; Yuhan Du; Yuxiang Wang; Xiao-Sheng Ni; Xianghao Meng; Xiangyu Jiang; Guangyi Wang; Congming Hao; Xinyi Wang; Pengcheng Zhang; Chunhui Pan; Haifeng Pan; Zhenrong Sun; Run Yang; Yang Xu; Yusheng Hou; Zhongbo Yan; Cheng Zhang; Hai-Zhou Lu; Junhao Chu; Xiang Yuan

doi:10.1038/s41467-024-46626-9

The discovery of three-dimensional Van Hove singularity

Nat Commun. 2024 Mar 14;15(1):2313. doi: 10.1038/s41467-024-46626-9.

Authors

Wenbin Wu^#^{1

2

3}, Zeping Shi^#¹, Mykhaylo Ozerov⁴, Yuhan Du¹, Yuxiang Wang⁵, Xiao-Sheng Ni⁶, Xianghao Meng¹, Xiangyu Jiang¹, Guangyi Wang¹, Congming Hao¹, Xinyi Wang¹, Pengcheng Zhang¹, Chunhui Pan⁷, Haifeng Pan¹, Zhenrong Sun¹, Run Yang⁸, Yang Xu², Yusheng Hou⁶, Zhongbo Yan⁶, Cheng Zhang^{5

9}, Hai-Zhou Lu¹⁰, Junhao Chu^{2

11}, Xiang Yuan^{12

13

14}

Affiliations

¹ State Key Laboratory of Precision Spectroscopy, East China Normal University, 200241, Shanghai, China.
² Key Laboratory of Polar Materials and Devices, Ministry of Education, School of Physics and Electronic Science, East China Normal University, 200241, Shanghai, China.
³ Shanghai Center of Brain-Inspired Intelligent Materials and Devices, East China Normal University, 200241, Shanghai, China.
⁴ National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, 32310, USA.
⁵ State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China.
⁶ Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices, School of Physics, Sun Yat-Sen University, 510275, Guangzhou, China.
⁷ Multifunctional Platform for Innovation Precision Machining Center, East China Normal University, 200241, Shanghai, China.
⁸ Key Laboratory of Quantum Materials and Devices of Ministry of Education, School of Physics, Southeast University, 211189, Nanjing, China.
⁹ Zhangjiang Fudan International Innovation Center, Fudan University, 201210, Shanghai, China.
¹⁰ Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology (SUSTech), 518055, Shenzhen, China.
¹¹ Institute of Optoelectronics, Fudan University, 200438, Shanghai, China.
¹² State Key Laboratory of Precision Spectroscopy, East China Normal University, 200241, Shanghai, China. xyuan@lps.ecnu.edu.cn.
¹³ Key Laboratory of Polar Materials and Devices, Ministry of Education, School of Physics and Electronic Science, East China Normal University, 200241, Shanghai, China. xyuan@lps.ecnu.edu.cn.
¹⁴ Shanghai Center of Brain-Inspired Intelligent Materials and Devices, East China Normal University, 200241, Shanghai, China. xyuan@lps.ecnu.edu.cn.

^# Contributed equally.

Abstract

Arising from the extreme/saddle point in electronic bands, Van Hove singularity (VHS) manifests divergent density of states (DOS) and induces various new states of matter such as unconventional superconductivity. VHS is believed to exist in one and two dimensions, but rarely found in three dimension (3D). Here, we report the discovery of 3D VHS in a topological magnet EuCd₂As₂ by magneto-infrared spectroscopy. External magnetic fields effectively control the exchange interaction in EuCd₂As₂, and shift 3D Weyl bands continuously, leading to the modification of Fermi velocity and energy dispersion. Above the critical field, the 3D VHS forms and is evidenced by the abrupt emergence of inter-band transitions, which can be quantitatively described by the minimal model of Weyl semimetals. Three additional optical transitions are further predicted theoretically and verified in magneto-near-infrared spectra. Our results pave the way to exploring VHS in 3D systems and uncovering the coordination between electronic correlation and the topological phase.