Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in underdoped Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)  

作　　者：Shiyuan Wang Yijun Yu Jinxiang Hao Keyi Liang Bingke Xiang Jinjiang Zhu Yishi Lin Yinping Pan Genda Gu Kenji Watanabe Takashi Taniguchi Yang Qi Yuanbo Zhang Yihua Wang 

机构地区：[1]State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China [2]Condensed Matter Physics and Materials Science Department,Brookhaven National Laboratory,Upton,NY 11973,USA [3]Research Center for Functional Materials,National Institute for Materials Science,Tsukuba 305-0044,Japan [4]International Center for Materials Nanoarchitectonics,National Institute for Materials Science,Tsukuba 305-0044,Japan [5]Shanghai Research Center for Quantum Sciences,Shanghai 201315,China

出　　处：《National Science Review》2024年第5期135-145,共11页国家科学评论（英文版）

基　　金：supported by the National Key Research and Development Program of China(2021YFA1400100);the National Natural Science Foundation of China(11827805 and 12150003);the Shanghai Municipal Science and Technology Major Project(2019SHZDZX01);support from the Elemental Strategy Initiative conducted by the Ministry of Education,Culture,Sports,Science and Technology of Japan(JPMXP0112101001);KAKENHI(JP19H05790 and JP20H00354);A3 Foresight by the Japan Society for the Promotion of Science;supported by the US Department of Energy,office of Basic Energy Sciences(DOE-sc0012704);financial support from the National Natural Science Foundation of China(11874115);financial support from the National Key Research and development Program of China(2018YFA0305600);the National Natural Science Foundation ofChina(U1732274 and 11527805);the ShanghaiMunicipal Science andTechnologyCommission(2019SHZDZX01);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB30000000);support from the China Postdoctoral Science Foundation(BX20180076 and 2018M641907).

摘　　要：Superconducting phase transitions in two dimensions lie beyond the description of the Ginzburg-Landau symmetry-breaking paradigm for three-dimensional superconductors.They are Berezinskii-Kosterlitz-Thouless(BKT)transitions of paired-electron condensate driven by the unbinding of topological excitations,i.e.vortices.The recently discovered monolayers of layered high-transition-temperature(T_(C))cuprate superconductor Bi_(2)Sr_(2)CaCu_(2)O_(8+δ)(Bi2212)meant that this 2D superconductor promised to be ideal for the study of unconventional superconductivity.But inhomogeneity posed challenges for distinguishing BKT physics from charge correlations in thismaterial.Here,we utilize the phase sensitivity of scanning superconducting quantum interference device microscopy susceptometry to image the local magnetic response of underdoped Bi2212 from the monolayer to the bulk throughout its phase transition.The monolayer segregates into domains with independent phases at elevated temperatures below T_(C).Within a single domain,we find that the susceptibility oscillates with flux between diamagnetism and paramagnetism in a Fraunhofer-like pattern up to T_(C).The finite modulation period,as well as the broadening of the peaks when approaching T_(C) from below,suggests well-defined vortices that are increasingly screened by the dissociation of vortex-antivortex plasma through a BKT transition.In the multilayers,the susceptibility oscillation differs in a small temperature regime below T_(C),consistent with a dimensional crossover led by interlayer coupling.Serving as strong evidence for BKT transition in the bulk,we observe a sharp jump in phase stiffness and paramagnetism at small fields just below T_(C).These results unify the superconducting phase transitions from themonolayer to the bulk underdoped Bi2212,and can be collectively referred to as the BKT transition with interlayer coupling.

关 键 词：cuprate superconductor MONOLAYER Berezinskii-Kosterlitz-Thouless transition scanning SQUID paramagneticMeissner effect 

分 类 号：O511[理学—低温物理]