Liu Fengshuo, Itahashi Yuki M, Aoki Shunta, Dong Yu, Wang Ziqian, Ogawa Naoki, Ideue Toshiya, Iwasa Yoshihiro
Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan.
Department of Physics, Fudan University, Shanghai 200433, China.
Sci Adv. 2024 Aug 2;10(31):eado1502. doi: 10.1126/sciadv.ado1502. Epub 2024 Jul 31.
In noncentrosymmetric superconductors, superconducting and normal conductions can interchange on the basis of the current flow direction. This effect is termed a superconducting diode effect (SDE), which is a focal point of recent research. The broken inversion and time-reversal symmetry is believed to be the requirements of SDE, but their intrinsic role has remained elusive. Here, we report strain-controlled SDEs in a layered trigonal superconductor, PbTaSe. The SDE was found exclusively in a strained device with its absence in an unstrained device despite that it is allowed in unstrained trigonal structure. Moreover, the zero-field or magnetic field-even (magnetic field-odd) SDE is observed when the strain and current are along armchair (zigzag) direction The results unambiguously demonstrate the intrinsic SDE under time-reversal symmetry and the critical role of strain-induced electric polarization.
在非中心对称超导体中，超导传导和正常传导可根据电流流动方向相互转换。这种效应被称为超导二极管效应（SDE），它是近期研究的一个焦点。人们认为，反演对称性和时间反演对称性的破缺是超导二极管效应的必要条件，但其内在作用仍不明确。在此，我们报告了层状三角超导体PbTaSe中应变控制的超导二极管效应。我们发现，该超导二极管效应仅出现在一个应变器件中，而在未应变器件中不存在，尽管未应变的三角结构允许出现这种效应。此外，当应变和电流沿扶手椅（之字形）方向时，会观察到零场或磁场偶数（磁场奇数）超导二极管效应。这些结果明确证明了时间反演对称性下的本征超导二极管效应以及应变诱导电极化的关键作用。
