Effect of Fermi surface topology change on the Kagome superconductor CeRu₂ under pressure

Journal Article · 23 December 2023 · Materials Today Physics

DOI: https://doi.org/10.1016/j.mtphys.2023.101322 · OSTI ID:2278833

Deng, Liangzi  ^[1]; Gooch, Melissa ^[1]; Liu, Hongxiong ^[2]; Salke, Nilesh P.  ^[3]; Bontke, Trevor ^[1]; Shao, Sen ^[4]; You, Jingyang ^[5]; Schulze, Daniel J. ^[1]; Kumar, Ravhi ^[3]; Yin, Jia-Xin ^[6]; Shi, Youguo ^[2]; Hemley, Russell J. ^[3]; Feng, Yuanping ^[5]; Chang, Guoqing ^[4]; Si, Qimiao ^[7]; Chu, Ching-Wu  ^[1]

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1. University of Houston, TX (United States)
2. Chinese Academy of Sciences, Beijing (China); University of Chinese Academy of Sciences, Beijing (China)
3. University of Illinois, Chicago, IL (United States)
4. Nanyang Technological University (Singapore)
5. National University of Singapore (Singapore)
6. Princeton University, NJ (United States); Southern University of Science and Technology, Guangdong (China)
7. Rice University, Houston, TX (United States)

The cubic Laves phase compound CeRu₂ with a Kagome substructure of Ru has been investigated to understand myriad fascinating phenomena resulting from competition among its various physical and geometric features. Such phenomena include flat bands, van Hove singularities, Dirac cones, reentrant superconductivity, magnetism, the Fulde–Ferrell–Larkin–Ovchinnikov state, valence fluctuations, time-irreversible anisotropic s-state superconductivity, etc. Extensive studies have thus been carried out since 1958 when the highly unusual coexistence of superconductivity and ferromagnetism was proposed for the mixed compounds (Ce,Gd)Ru₂. Activity has accelerated in recent years due to increasing interest in topological states in superconductors. However, there has been little investigation of the mutual influence of these fascinating states. Therefore, we systematically investigated the superconductivity and possible Fermi surface topological change in CeRu₂ via magnetic, resistivity, and structural measurements under pressure up to ~168 GPa. An unusual phase diagram that suggests an intriguing interplay between the compound’s superconducting order and Fermi surface topological order has been constructed. A resurgence in its superconducting transition temperature was observed above 28 GPa. Our experiments have identified a structural transition above 76 GPa and a few tantalizing phase transitions driven by high pressure. Our high-pressure results further suggest that superconductivity and Fermi surface topology in CeRu₂ are strongly intertwined.

• Research Organization: University of Illinois, Chicago, IL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP); US Air Force Office of Scientific Research (AFOSR); National Natural Science Foundation of China (NSFC); National Science Foundation (NSF); Robert A. Welch Foundation
• Grant/Contract Number: NA0003975; FA9550-15-1-0236; FA9550-20-1-0068; U2032204; DMR-2104881; FA9550-21-1-0356; C-1411
• OSTI ID: 2278833
• Journal Information: Materials Today Physics, Vol. 40; ISSN 2542-5293
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English