表面K原子吸附的多层FeSe薄膜的超导性质  

Superconductivity of multilayer FeSe film adsorbed by potassium on the surface

作　　者：姚钢 刘灿华 贾金锋 YAO Gang;LIU Can-hua;JIA Jin-feng(Key Laboratory of Artificial Structures and Quantum Control(Ministry of Education),Shenyang National Laboratory for Materials Science,School of Physics and Astronomy,Shanghai Jiao Tong University,Shanghai 200240;Collaborative Innovation Center of Advanced Microstructures,Nanjing Jiangsu 210093;Tsung-Dao Lee Institute,Shanghai 200240,China)

机构地区：[1]人工结构及量子调控教育部重点实验室,沈阳材料科学国家研究中心,上海交通大学物理与天文学院,上海200240 [2]人工微结构科学与技术协同创新中心,江苏南京210093 [3]李政道研究所,上海200240

出　　处：《电子显微学报》2020年第5期577-585,共9页Journal of Chinese Electron Microscopy Society

基　　金：国家重点基础研究发展计划(Nos.2016YFA0301003,2016YFA0300403);国家自然科学基金资助项目(Nos.11521404,11634009,U1632102,11674222,11574202,11674226,11874256,11874258,11861161003,11790313);中国科学院战略性先导科技专项(B类)资助项目(No.XDB28000000);中国科学院重点研究项目(No.XDPB08-2);上海人才计划支持。

摘　　要：本文简要介绍了在上海交通大学低维物理与界面工程实验室对表面吸附有K原子的多层FeSe薄膜所做的充分的实验研究,旨在理解铁基高温超导体的性质。由于碱金属原子电负性较小,很容易将一部分电子转移出去。近年来,国际上多个研究组发现在FeSe薄膜或块体表面蒸镀适量的碱金属原子可以增大超导能隙。基于此,控制碱金属原子的吸附量有望实现对FeSe层超导电性的调控。作者利用分子束外延技术制备了高质量的多层FeSe薄膜,通过表面K吸附实现掺入电子后,对该体系的超导转变温度Tc、磁场穿透深度λ、超流密度ρs,特征转变场■与超导能隙ΔE等超导参量随K吸附量或温度的变化进行了系统分析,实验结果对铁基高温超导的理解具有重要意义。A brief account is given of an extensive experiment on the multilayer FeSe film adsorbed by potassium on the surface performed in Laboratory of Low Dimensional Physics and Interface Engineering, Shanghai Jiao Tong University, in order to understanding the nature of the superconductors derived from FeSe. Due to the low electronegativityof alkali metal atoms, they can easily transfer part of electrons out. For the past few years, several international research groups reported that potassium adsorbed on FeSe film or crystal surfaces can enlarge the superconducting energy gap. The controllability of superconductivity of FeSe layer could eventually be realized based on the strategy. Here we report a systematically investigation on the superconductivity in multilayer FeSe prepared by molecular beam epitaxy, and the carrier concentration was tuned by surface K adsorption. Our results deduced from the dependence of T_c, magnetic penetration depth(λ), superfluid density(ρ_s), characteristic magnetic field(■) as well as superconducting energy gap(ΔΕ) on the surface K coverage provides the crucial information for understanding the superconductivity of the superconductors derived from FeSe.

关 键 词：高温超导电性 相图 配对对称性 相位刚度 

分 类 号：O484.1[理学—固体物理] O484.5[理学—物理]