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  

作　　者：詹红星 林玉尺 赵宇清 左海艳 王兴玉 马肖燕 李春红 罗会仟 陈根富 李世亮 任聪 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(School of Physics and Astronomy,Yunnan University,Kunming 650500,China;Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;Yunnan Key Laboratory for Electromagnetic Materials and Devices,Yunnan University,Kunming 650500,China)

机构地区：[1]School of Physics and Astronomy,Yunnan University,Kunming 650500,China [2]Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [3]Yunnan Key Laboratory for Electromagnetic Materials and Devices,Yunnan University,Kunming 650500,China

出　　处：《Chinese Physics Letters》2024年第4期118-123,共6页中国物理快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.11774303 and 11574373);the National Key Research and Development Program of China(Grant Nos.2022YFA1403402,2021YFA1400401,and 2020YFA0406003);the Chinese Academy of Sciences(Grant Nos.XDB33000000 and GJTD-2020-01);financial support from the Joint Fund of Yunnan Provincial Science and Technology Department(Grant No.2019FY003008)。

摘　　要：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 quantum critical point.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 reveals 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 Ω_(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 the BaFe_(2)(As_(1-x)P_(x))_(2) system.

关 键 词：quantum critical RESISTIVITY 

分 类 号：O511.3[一般工业技术—材料科学与工程]