通过非互易输运揭示隐藏的非常规配对
Revealing Hidden Unconventional Pairing through Nonreciprocal Transport
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中文总结 AI 辅助
本文开发了一种对称分辨框架，利用多端器件的非互易电导识别超导配对对称性，可区分单重态与自旋三重态配对，为揭示隐藏的非常规配对提供了新探针。
中文摘要 AI 辅助
识别库珀对的配对对称性是理解非常规超导体微观机制的基础步骤。然而，实验识别仍是一项艰巨挑战，尤其是当非常规配对被主导的s波分量掩盖其光谱特征时。本文中，我们开发了一种对称分辨框架，用于通过多端器件中源极和探测器端互换时的非互易电导来识别超导配对对称性。我们表明，非互易输运源于超导序参量的对称破缺分量，并呈现出编码配对能隙动量空间结构的特征角依赖关系。特别地，时间反演破缺的单重态配对会诱导非互易电荷输运，而自旋三重态配对会产生非互易自旋响应，为潜在序参量提供了不同的输运指纹。我们使用铁基超导体和非中心对称超导体的代表性模型演示了该机制，并概述了多端测量的实验方案。我们的结果推进了对超导体中非互易输运的理论理解，并确立其作为对称选择性探针，用于识别广泛超导材料中隐藏的非常规配对。
英文摘要
Identifying the pairing symmetry of Cooper pairs is a fundamental step toward understanding the microscopic mechanisms of unconventional superconductors. However, experimental identification remains a formidable challenge, particularly when unconventional pairing is obscured by a dominant $s$-wave component that masks its spectroscopic signatures. Here, we develop a symmetry-resolved framework to identify superconducting pairing symmetry through nonreciprocal conductance upon exchanging source and detector terminals in multiterminal devices. We show that nonreciprocal transport arises from symmetry-breaking components of the superconducting order parameter and exhibits a characteristic angular dependence that encodes the momentum-space structure of the pairing gap. In particular, time-reversal-breaking singlet pairing induces nonreciprocal charge transport, while spin-triplet pairing generates nonreciprocal spin responses, providing distinct transport fingerprints of the underlying order. We demonstrate this mechanism using representative models of iron-based and noncentrosymmetric superconductors and outline experimental protocols for multiterminal measurements. Our results advance the theoretical understanding of nonreciprocal transport in superconductors, and establish it as a symmetry-selective probe for identifying hidden unconventional pairing in a wide range of superconducting materials.
