发表机构
National Yang Ming Chiao Tung University; National Center for Theoretical Sciences（国立阳明交通大学; 国家理论科学中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过自洽求解Bogoliubov-de Gennes与麦克斯韦方程，研究清洁铁磁/铁磁/超导自旋阀中的电磁邻近效应，发现中心铁磁层主导自发电流，电磁响应贯穿超导层并影响长程奇频三重态。
AI 中文摘要
当铁磁体与超导体接触时，超导邻近效应会引发多种有趣的现象，包括振荡的单态库珀对振幅，以及由铁磁体中交换相互作用诱导的长程奇频三重态关联。然而，从电动力学的角度来看，理解自发电流何时以及如何产生同样重要。为了研究电磁邻近效应与常规超导邻近效应之间的相互作用，我们研究了清洁的铁磁/铁磁/超导体自旋阀异质结构，其中两个铁磁层之间的相对角度可以调节。我们的方法基于耦合的Bogoliubov-de Gennes方程和麦克斯韦方程的自洽数值求解，提供了一种能够在原子尺度上解析物理的微观描述。出现了几个显著特征。在弱交换场和强交换场两种情况下，当中心铁磁层的交换场强度变化时，该层在产生可观的自发电流中起主导作用。我们进一步发现，由此产生的电磁响应延伸至整个超导层，这与短程的反向邻近效应形成鲜明对比。在非共线构型中，电磁邻近效应还重新配置了局部磁场方向，并减小了两个铁磁层中磁场之间的角度失配。因此，长程奇频三重态振幅受到轨道响应的修正，轨道响应通过改变准粒子态的动量空间结构来改变其底层准粒子态。最后，我们的框架可以自然地推广到其他超导自旋电子学系统，可能包括约瑟夫森结和交变磁体/超导体异质结构。
英文摘要
When ferromagnets are brought into contact with a superconductor, superconducting proximity effects give rise to a variety of interesting phenomena, including oscillatory singlet Cooper-pair amplitudes and long-ranged odd-frequency triplet correlations induced by the exchange interactions in the ferromagnets. From an electrodynamic perspective, however, it is equally important to understand when and how spontaneous currents can emerge. To investigate the interplay between electromagnetic and conventional superconducting proximity effects, we study clean ferromagnet/ferromagnet/superconductor spin-valve heterostructures in which the relative angle between the two ferromagnetic layers can be tuned. Our approach is based on a self-consistent numerical solution of the coupled Bogoliubov-de Gennes and Maxwell equations, providing a microscopic description capable of resolving physics on atomic length scales. Several notable features emerge. In both the weak- and strong-exchange-field regimes, the central ferromagnetic layer plays a dominant role in generating sizable spontaneous currents when its exchange-field strength is varied. We further find that the resulting electromagnetic response extends across the entire superconducting layer, in sharp contrast to the short-ranged inverse proximity effect. In noncollinear configurations, the electromagnetic proximity effect also reconfigures the local magnetic-field orientation and reduces the angular mismatch between the fields in the two ferromagnetic layers. The long-ranged odd-frequency triplet amplitudes are consequently modified by the orbital response, which alters the underlying quasiparticle states by changing their momentum-space structure. Finally, our framework can be naturally generalized to other superconducting spintronic systems, possibly including Josephson junctions and altermagnet/superconductor heterostructures.
