Revealing the A1g-type strain effect on superconductivity and nematicity in FeSe thin flake  

作　　者：Zhaohui Cheng Bin Lei Xigang Luo Jianjun Ying Zhenyu Wang Tao Wu Xianhui Chen 程朝晖;雷彬;罗习刚;应剑俊;王震宇;吴涛;陈仙辉(CAS Key Laboratory of Strongly-coupled Quantum Matter Physics,Department of Physics,University of Science and Technology of China,Hefei 230026,China;Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China;CAS Center for Excellence in Superconducting Electronics(CENSE),Shanghai 200050,China;CAS Center for Excellence in Quantum Information and Quantum Physics,Hefei 230026,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)

机构地区：[1]CAS Key Laboratory of Strongly-coupled Quantum Matter Physics,Department of Physics,University of Science and Technology of China,Hefei 230026,China [2]Hefei National Laboratory for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,China [3]CAS Center for Excellence in Superconducting Electronics(CENSE),Shanghai 200050,China [4]CAS Center for Excellence in Quantum Information and Quantum Physics,Hefei 230026,China [5]Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China

出　　处：《Chinese Physics B》2021年第9期56-61,共6页中国物理B（英文版）

基　　金：Project supported by the National Key R&D Program of China(Grant Nos.2017YFA0303000 and 2016YFA0300201);the National Natural Science Foundation of China(Grant No.11888101);the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB25000000);the Anhui Initiative in Quantum Information Technologies(Grant No.AHY160000).

摘　　要：The driving mechanism of nematicity and its twist with superconductivity in iron-based superconductors are still under debate.Recently,a dominant B1g-type strain effect on superconductivity is observed in underdoped iron-pnictides superconductors Ba(Fe_(1-x)Co_(x))_(2)As_(2),suggesting a strong interplay between nematicity and superconductivity.Since the long-range spin order is absent in FeSe superconductor,whether a similar strain effect could be also observed or not is an interesting question.Here,by utilizing a flexible film as substrate,we successfully achieve a wide-range-strain tuning of FeSe thin flake,in which both the tensile and compressive strain could reach up to~0.7%,and systematically study the strain effect on both superconducting and nematic transition(T_(c)and Ts)in the FeSe thin flake.Our results reveal a predominant A1g-type strain effect on T_(c).Meanwhile,Ts exhibits a monotonic anti-correlation with T_(c)and the maximum T_(c)reaches to 12 K when Ts is strongly suppressed under the maximum compressive strain.Finally,in comparison with the results in the underdoped Ba(Fe_(1-x)Co_(x))_(2)As_(2),the absence of B1g-type strain effect in FeSe further supports the role of stripe-type spin fluctuations on superconductivity.In addition,our work also supports that the orbital degree of freedom plays a key role to drive the nematic transition in FeSe.

关 键 词：iron-based superconductors SUPERCONDUCTIVITY electronic nematicity strain effect 

分 类 号：O511.3[一般工业技术—材料科学与工程]