Anisotropic $s$-wave gap in the vicinity of a quantum critical point in superconducting BaFe$_{2}$(As$_{1-x}$P$_{x}$)$_2$ single crystals: a study of point-contact spectroscopy
{"title":"Anisotropic $s$-wave gap in the vicinity of a quantum critical point in superconducting BaFe$_{2}$(As$_{1-x}$P$_{x}$)$_2$ single crystals: a study of point-contact spectroscopy","authors":"Hong-xing Zhan, Yu-chi Lin, Yu-qing Zhao, Hai-yan Zuo, Xing-yu Wang, Xiao-yan Ma, Chun-hong Li, Hui-qian Luo, Gen-fu Chen, Shi-liang Li, Cong Ren","doi":"10.1088/0256-307x/41/4/047402","DOIUrl":null,"url":null,"abstract":"\n Here we report on soft $c$-axis point-contact Andreev reflection (PCAR) spectroscopy combining with resistivity measurements on BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$, to elucidate the superconducting gap structure in the vicinity of the QCP. A double-peak at the gap edge plus a dip feature at zero-bias has been observed on the PCAR spectra, indicative of the presence of a nodeless gap in BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$. Detailed analysis within a sophisticated theoretical model reveal an anisotropic gap with deep gap minima. The PCARs also feature additional structures related to the electron-bosonic coupling mode. Using the extracted superconducting energy gap value, a characteristic bosonic energy $\\Omega_{b}$ and its temperature dependence are obtained, comparable with the spin-resonance energy observed in neutron scattering experiment. These results indicate a magnetism-driven quantum critical point in BaFe$_2$(As$_{1-x}$P$_x$)$_2$ system.","PeriodicalId":10344,"journal":{"name":"Chinese Physics Letters","volume":null,"pages":null},"PeriodicalIF":3.5000,"publicationDate":"2024-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chinese Physics Letters","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1088/0256-307x/41/4/047402","RegionNum":2,"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}
引用次数: 0
Abstract
Here we report on soft $c$-axis point-contact Andreev reflection (PCAR) spectroscopy combining with resistivity measurements on BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$, to elucidate the superconducting gap structure in the vicinity of the QCP. A double-peak at the gap edge plus a dip feature at zero-bias has been observed on the PCAR spectra, indicative of the presence of a nodeless gap in BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$. Detailed analysis within a sophisticated theoretical model reveal an anisotropic gap with deep gap minima. The PCARs also feature additional structures related to the electron-bosonic coupling mode. Using the extracted superconducting energy gap value, a characteristic bosonic energy $\Omega_{b}$ and its temperature dependence are obtained, comparable with the spin-resonance energy observed in neutron scattering experiment. These results indicate a magnetism-driven quantum critical point in BaFe$_2$(As$_{1-x}$P$_x$)$_2$ system.
期刊介绍:
Chinese Physics Letters provides rapid publication of short reports and important research in all fields of physics and is published by the Chinese Physical Society and hosted online by IOP Publishing.