Preformed Cooper pairs in a triclinic iron pnictide superconductor  

作　　者：Zezhong Li Wenshan Hong Honglin Zhou Xiaoyan Ma Uwe Stuhr Kaiyue Zeng Long Ma Ying Xiang Huan Yang Hai-Hu Wen Jiangping Hu Shiliang Li Huiqian Luo 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China [4]Laboratory for Neutron Scattering and Imaging,Paul Scherrer Institute,Villigen PSI CH-5232,Switzerland [5]Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions,High Magnetic Field Laboratory,Chinese Academy of Sciences,Hefei 230031,China [6]National Laboratory of Solid State Microstructures and Department of Physics,Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China [7]Songshan Lake Materials Laboratory,Dongguan 523808,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2025年第4期198-210,共13页中国科学:物理学、力学、天文学(英文版)

基　　金：supported by the National Key Research and Development Program of China(Grant Nos.2023YFA1406100,2018YFA0704200;2020YFA0406000);the National Natural Science Foundation of China(Grant Nos.11822411,11874057,and 11961160699);the Strategic Priority Research Program(B)of the CAS(Grant Nos.XDB25000000;XDB33000000);the K.C.Wong Education Foundation(Grant No.GJTD-2020-01);the support from the Youth Innovation Promotion Association of CAS(Grant No.Y202001);the support from the Postdoctoral Innovative Talent program(Grant No.BX2021018);the China Postdoctoral Science Foundation(Grant No.2021M700250)。

摘　　要：Electron pairing along with phase coherence generates superconductivity below the critical temperature(T_(c)).In underdoped highT_ccuprates,these two quantum phenomena may occur at separate temperatures,which was lately confirmed in the quasi-twodimensional(quasi-2D)iron chalcogenide superconductors.Here,we report a systematic investigation on the pre-pairing behavior in a triclinic iron pnictide superconductor(Ca_(0.85)La_(0.15))_(10)(Pt_(3)As_(8))(Fe_(2)As_(2))_(5)with T_(c)≈30 K,where the superconductivity is quasi-2D manifested by the Berezinskii-Kosterlitz-Thouless behaviors.Inelastic neutron scattering experiments unambiguously reveal a spin resonance peak around E_(R)=13 me V in the superconducting state,but its intensity continuously decreases when warming up across T_(c),accompanied with an anomaly around T^(*)≈45 K in spin correlations,and a suppression by an in-plane magnetic field persisting to the same temperature.Below T^(*),a significant Nernst signal and a reduction of density of states at the Fermi level are also observed.These results suggest that the precursor of spin resonance is highly related to the preformed Cooper pairs driven by phase fluctuations,much like the pseudogap case in cuprates.

关 键 词：iron-based superconductors pnictides and chalcogenides nuclear magnetic resonance neutron inelastic scattering pseudogap regime 

分 类 号：O469[理学—凝聚态物理]