{"title":"光电发射揭示CaKFe4As4中电子-自旋涨落耦合","authors":"Peng Li, Yuzhe Wang, Yabin Liu, Jianghao Yao, Zhisheng Zhao, Zhengtai Liu, Dawei Shen, Huiqian Luo, Guanghan Cao, Juan Jiang, Donglai Feng","doi":"10.1103/physrevx.15.021001","DOIUrl":null,"url":null,"abstract":"Electron-boson coupling in unconventional superconductors is one of the key parameters in understanding the superconducting pairing symmetry. Here, we report definitive photoemission evidence of electron-spin fluctuation coupling in the iron-based superconductor CaKFe</a:mi></a:mrow>4</a:mn></a:msub>As</a:mi></a:mrow>4</a:mn></a:msub></a:mrow></a:math>, obtained via high-resolution ARPES. Our study identifies a distinct kink structure on the <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mi>α</c:mi></c:math> band, observable only in the superconducting phase and closely linked with the superconductivity, indicative of strong electron-boson interactions. Notably, this kink structure corresponds to two distinct bosonic modes at 11 meV and 13 meV, aligning with spin resonance modes previously observed in inelastic neutron-scattering experiments. This alignment underscores the significant role of antiferromagnetic fluctuations in the pairing mechanism of this superconductor. Furthermore, the unique momentum-dependent and orbital-selective properties of the coupling revealed by ARPES provide profound insights into the pairing symmetry, suggesting predominantly <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:msub><e:mrow><e:mi>s</e:mi></e:mrow><e:mrow><e:mo>±</e:mo></e:mrow></e:msub></e:mrow></e:math>-wave pairing facilitated by spin fluctuations. Our findings not only highlight the pivotal role of spin resonance in the superconductivity of <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mrow><g:msub><g:mrow><g:mi>CaKFe</g:mi></g:mrow><g:mn>4</g:mn></g:msub><g:msub><g:mrow><g:mi>As</g:mi></g:mrow><g:mn>4</g:mn></g:msub></g:mrow></g:math> but also enhance our understanding of the electron-spin fluctuation interactions in unconventional superconductors. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"19 1","pages":""},"PeriodicalIF":11.6000,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Revealing the Electron-Spin Fluctuation Coupling by Photoemission in CaKFe4As4\",\"authors\":\"Peng Li, Yuzhe Wang, Yabin Liu, Jianghao Yao, Zhisheng Zhao, Zhengtai Liu, Dawei Shen, Huiqian Luo, Guanghan Cao, Juan Jiang, Donglai Feng\",\"doi\":\"10.1103/physrevx.15.021001\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Electron-boson coupling in unconventional superconductors is one of the key parameters in understanding the superconducting pairing symmetry. Here, we report definitive photoemission evidence of electron-spin fluctuation coupling in the iron-based superconductor CaKFe</a:mi></a:mrow>4</a:mn></a:msub>As</a:mi></a:mrow>4</a:mn></a:msub></a:mrow></a:math>, obtained via high-resolution ARPES. Our study identifies a distinct kink structure on the <c:math xmlns:c=\\\"http://www.w3.org/1998/Math/MathML\\\" display=\\\"inline\\\"><c:mi>α</c:mi></c:math> band, observable only in the superconducting phase and closely linked with the superconductivity, indicative of strong electron-boson interactions. Notably, this kink structure corresponds to two distinct bosonic modes at 11 meV and 13 meV, aligning with spin resonance modes previously observed in inelastic neutron-scattering experiments. This alignment underscores the significant role of antiferromagnetic fluctuations in the pairing mechanism of this superconductor. Furthermore, the unique momentum-dependent and orbital-selective properties of the coupling revealed by ARPES provide profound insights into the pairing symmetry, suggesting predominantly <e:math xmlns:e=\\\"http://www.w3.org/1998/Math/MathML\\\" display=\\\"inline\\\"><e:mrow><e:msub><e:mrow><e:mi>s</e:mi></e:mrow><e:mrow><e:mo>±</e:mo></e:mrow></e:msub></e:mrow></e:math>-wave pairing facilitated by spin fluctuations. Our findings not only highlight the pivotal role of spin resonance in the superconductivity of <g:math xmlns:g=\\\"http://www.w3.org/1998/Math/MathML\\\" display=\\\"inline\\\"><g:mrow><g:msub><g:mrow><g:mi>CaKFe</g:mi></g:mrow><g:mn>4</g:mn></g:msub><g:msub><g:mrow><g:mi>As</g:mi></g:mrow><g:mn>4</g:mn></g:msub></g:mrow></g:math> but also enhance our understanding of the electron-spin fluctuation interactions in unconventional superconductors. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>\",\"PeriodicalId\":20161,\"journal\":{\"name\":\"Physical Review X\",\"volume\":\"19 1\",\"pages\":\"\"},\"PeriodicalIF\":11.6000,\"publicationDate\":\"2025-04-02\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physical Review X\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1103/physrevx.15.021001\",\"RegionNum\":1,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physical Review X","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1103/physrevx.15.021001","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
Revealing the Electron-Spin Fluctuation Coupling by Photoemission in CaKFe4As4
Electron-boson coupling in unconventional superconductors is one of the key parameters in understanding the superconducting pairing symmetry. Here, we report definitive photoemission evidence of electron-spin fluctuation coupling in the iron-based superconductor CaKFe4As4, obtained via high-resolution ARPES. Our study identifies a distinct kink structure on the α band, observable only in the superconducting phase and closely linked with the superconductivity, indicative of strong electron-boson interactions. Notably, this kink structure corresponds to two distinct bosonic modes at 11 meV and 13 meV, aligning with spin resonance modes previously observed in inelastic neutron-scattering experiments. This alignment underscores the significant role of antiferromagnetic fluctuations in the pairing mechanism of this superconductor. Furthermore, the unique momentum-dependent and orbital-selective properties of the coupling revealed by ARPES provide profound insights into the pairing symmetry, suggesting predominantly s±-wave pairing facilitated by spin fluctuations. Our findings not only highlight the pivotal role of spin resonance in the superconductivity of CaKFe4As4 but also enhance our understanding of the electron-spin fluctuation interactions in unconventional superconductors. Published by the American Physical Society2025
期刊介绍:
Physical Review X (PRX) stands as an exclusively online, fully open-access journal, emphasizing innovation, quality, and enduring impact in the scientific content it disseminates. Devoted to showcasing a curated selection of papers from pure, applied, and interdisciplinary physics, PRX aims to feature work with the potential to shape current and future research while leaving a lasting and profound impact in their respective fields. Encompassing the entire spectrum of physics subject areas, PRX places a special focus on groundbreaking interdisciplinary research with broad-reaching influence.