Diamagnetic response of a superconducting surface superstructure: Si(111)-root 7 x root 3-In
Diamagnetic response of a superconducting surface superstructure: Si(111)-root 7 x root 3-In
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超导表面超结构的抗磁响应：Si(111)-root 7 x root 3-In
DOI：
10.1103/physrevb.99.140506
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发表时间：
2019
影响因子：
3.7
通讯作者：
Jia Jin Feng
中科院分区：
文献类型：
--
作者：
Wu Yanfu;Duan Ming Chao;Liu Ningning;Yao Gang;Guan D;an;Wang Shiyong;Li Yao Yi;Zheng Hao;Liu Canhua;Jia Jin Feng
各种超薄膜在终极二维极限下的宏观超导性，即由单晶表面支撑的厚度仅为一个或两个原子层的薄膜，已在仅零电阻的实验中表现出来，但由于缺乏适当的原位技术，尚未表现出迈斯纳效应，尽管这两种现象都是超导体的定义特征。利用自主研发的多功能扫描隧道显微镜，我们成功地检测到了Si(111)表面双原子层铟薄膜的宏观超电流和抗磁响应。抗磁测量表明，在肮脏极限下，穿透深度的低温变化遵循 Bardeen-Cooper-Schrieffer 理论。根据零温度穿透深度的磁场依赖性，断对相互作用的大小被确定为 0.80，这意味着配对对称性稍微偏离各向同性波。目前的工作表明，可以在易受空气影响的超薄超导薄膜中观察到迈斯纳效应，这对于详细理解微观配对机制非常有帮助。
Macroscopic superconductivity in various ultrathin films at the ultimate two-dimensional limit, i.e., films with thickness of only one- or two-atomic layers supported by single-crystal surfaces, has manifested itself in experiments with only zero resistance but not yet with the Meissner effect due to the lack of a properin situtechnique, although both phenomena are the defining characteristics of a superconductor. Using a self-developed multifunctional scanning tunneling microscope, we succeeded in detecting not only the macroscopic supercurrent but also diamagnetic response of a two-atomic-layer indium film on a Si(111) surface. The diamagnetic measurements reveal that the low-temperature variation of penetration depth follows the Bardeen-Cooper-Schrieffer theory in the dirty limit. The magnitude of the pair-breaking interaction is determined to be 0.80 from the magnetic field dependence of the zero-temperature penetration depth, which implies that the pairing symmetry deviates slightly from an isotropicwave. The present work demonstrates that it is possible to observe the Meissner effect in ultrathin superconducting films that are vulnerable to air, which is very helpful for a detailed understanding of the microscopic pairing mechanism.