Coexistence of near- E F Flat Band and Van Hove Singularity in a Two-Phase Superconductor

Chen, Xuezhi1,2,3; Wang, Le4,5; Ishizuka, Jun6; Zhang, Renjie2,3,7,8; Nogaki, Kosuke9; Cheng, Yiwei1,2,3; Yang, Fazhi2; Chen, Zhenhua10; Zhu, Fangyuan; Liu, Zhengtai10; Mei, Jiawei5; Yanase, Youichi9; Lv, Baiqing2,11,12; Huang, Yaobo10

2024-06-20

10.1103/PhysRevX.14.021048

PHYSICAL REVIEW X   影响因子和分区

2160-3308

Quantum many -body systems, particularly, the ones with large near- E F density states, are well known for exhibiting rich phase diagrams as a result of enhanced electron correlations. The recently discovered locally noncentrosymmetric heavy fermion superconductor CeRh 2 As 2 has stimulated extensive attention due to its unusual H -T phase diagram consisting of two-phase superconductivity, antiferromagnetic order, and possible quadrupole -density wave orders. However, the critical near- E F electronic structure remains experimentally elusive. Here, we provide this key information by combining soft -x-ray and vacuum ultraviolet (VUV) angle-resolved-photoemission-spectroscopy measurements and atomresolved density -functional -theory & eth; DFT & THORN; & thorn; U calculations. With bulk -sensitive soft x ray, we reveal quasi -2D hole and electron pockets near the E F . On the other hand, under VUV light, the Ce flat bands are resolved with the c -f hybridization persisting up to well above the Kondo temperature. Most importantly, we observe a symmetry -protected fourfold Van Hove singularity (VHS) coexisting with the Ce 4 f 15/2 flat bands at the X point, which, to the best of our knowledge, has never been reported before. Such a rare coexistence is expected to lead to a large density of states at the zone edge, a large upper critical field of the odd -parity phase, as well as spin and/or charge instabilities with a vector of (1 / 2, 1 / 2, 0). Uniquely, it will also result in a new type of f - VHS hybridization that alters the order and fine electronic structure of the VHS and flat bands. Our findings provide not only key insights into the nature of multiple phases in CeRh 2 As 2 but also open up new prospects for exploring the novelties of many -body systems with f - VHS hybridization.

SCI ; EI

英语

其他

Shanghai Committee of Science and Technology[23JC1403300] ; Ministry of Science and Technology of China[2023YFA1407400] ; National Natural Science Foundation of China["12204223","12374063"] ; Shanghai Natural Science Fund for Original Exploration Program[23ZR1479900] ; JSPS KAKENHI["JP21J23007","JP22H01181","JP22H04933"]

Physics

Physics, Multidisciplinary

WOS:001252492900002

AMER PHYSICAL SOC

Web of Science

1.Chinese Acad Sci, Shanghai Inst Appl Phys, Shanghai 201800, Peoples R China
2.Shanghai Jiao Tong Univ, Tsung Dao Lee Inst, Shanghai 200240, Peoples R China
3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China
4.Southern Univ Sci & Technol, Shenzhen Inst Quantum Sci & Engn, Shenzhen 518055, Peoples R China
5.Int Quantum Acad, Shenzhen 518048, Peoples R China
6.Niigata Univ, Fac Engn, Ikarashi, Niigata 9502181, Japan
7.Chinese Acad Sci, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China
8.Chinese Acad Sci, Inst Phys, Beijing 100190, Peoples R China
9.Kyoto Univ, Dept Phys, Kyoto 6068502, Japan
10.Chinese Acad Sci, Shanghai Adv Res Inst, Shanghai Synchrotron Radiat Facil, Shanghai 201204, Peoples R China
11.Shanghai Jiao Tong Univ, Sch Phys & Astron, Shanghai 200240, Peoples R China
12.Shanghai Jiao Tong Univ, Zhangjiang Inst Adv Study, Shanghai 200240, Peoples R China

Chen, Xuezhi,Wang, Le,Ishizuka, Jun,et al. Coexistence of near- E F Flat Band and Van Hove Singularity in a Two-Phase Superconductor[J]. PHYSICAL REVIEW X,2024,14(2).

Chen, Xuezhi.,Wang, Le.,Ishizuka, Jun.,Zhang, Renjie.,Nogaki, Kosuke.,...&Huang, Yaobo.(2024).Coexistence of near- E F Flat Band and Van Hove Singularity in a Two-Phase Superconductor.PHYSICAL REVIEW X,14(2).

Chen, Xuezhi,et al."Coexistence of near- E F Flat Band and Van Hove Singularity in a Two-Phase Superconductor".PHYSICAL REVIEW X 14.2(2024).