发表机构
University of Wisconsin-Madison; Hebrew University of Jerusalem（威斯康星大学麦迪逊分校; 耶路撒冷希伯来大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究揭示伊辛超导体中磁场诱导的$s+if$配对产生超导二极管效应，通过构建金兹堡-朗道理论阐明其机制，该效应可作为探测三重态配对通道的输运探针。
AI 中文摘要
伊辛超导体的面内临界场比泡利极限高出一个数量级，因为伊辛自旋轨道耦合将电子自旋锁定在基平面外。这种锁定效应也将面内塞曼场转化为等量自旋三重态库珀对的来源，使得场诱导的凝聚态具有$s+if$特性。我们表明，这种转化通道还会产生 Lifshitz 不变量，即金兹堡-朗道展开中对超导二极管效应负责的奇动量项。当单层的基平面对称性被衬底或栅极打破时，场诱导的三重态与库珀对动量线性耦合，从而产生本征二极管响应，其强度由塞曼能与自旋轨道能的比值决定，而非宇称混合机制中常见的自旋轨道能与费米能的小比值。我们构建了对称约束的双分量金兹堡-朗道理论，描述耦合的单重态和三重态序参量，并从伊辛超导体的微观模型中推导出其所有系数；完整的泛函（包括所有梯度项和四次项）由温度、场和库珀对动量的单一对破缺函数生成。吸引性的三重态通道会改变二极管响应：在弱场下，它通过直接路径与集体模式转化路径之间的相消干涉抑制效率；在强场下，它将二极管 regime 扩展到远超仅单重态的临界场，最大效率在三重态增强的相界处达到。因此，二极管效应可作为探测隐藏三重态配对通道和场诱导$s+if$态的输运探针。
英文摘要
The in-plane critical field of Ising superconductors exceeds the Pauli limit by an order of magnitude because the Ising spin-orbit coupling locks the electron spins out of the basal plane. The same locking converts an in-plane Zeeman field into a source of equal-spin triplet Cooper pairs, so that the field-driven condensate acquires an $s+if$ character. We show that this conversion channel also generates Lifshitz invariants, the odd-in-momentum terms of the Ginzburg-Landau expansion responsible for the superconducting diode effect. When the basal mirror symmetry of the monolayer is lifted by a substrate or a gate, the field-induced triplets couple linearly to the Cooper-pair momentum, and an intrinsic diode response develops whose strength is set by the ratio of the Zeeman and spin-orbit energies rather than by the small ratio of the spin-orbit and Fermi energies familiar from parity-mixing mechanisms. We construct the symmetry-constrained two-component Ginzburg-Landau theory of the coupled singlet and triplet order parameters and derive all of its coefficients from the microscopic model of an Ising superconductor; the complete functional, including all gradient and quartic terms, is generated by a single pair-breaking function of temperature, field, and Cooper-pair momentum. An attractive triplet channel reshapes the diode response: at weak fields it suppresses the efficiency through destructive interference between the direct and the collective-mode conversion paths, while at strong fields it extends the diode regime well beyond the singlet-only critical field, with the maximal efficiency reached along the triplet-enhanced phase boundary. The diode effect thereby serves as a transport probe of a hidden triplet pairing channel and of the field-induced $s+if$ state.
Comments13 pages, 3 figures
