标题： 铁磁体/超导体/正常金属三明治结构中的交流/直流自旋电流 显示英文标题

标题： AC/DC spin current in ferromagnet/superconductor/normal metal trilayer systems

摘要： 自旋泵浦与超导体已被广泛研究，特别是在双层系统中。 在本研究中，我们研究了由铁磁绝缘体（FMI）、超导体（SC）和正常金属（NM）组成的三层系统中的自旋泵浦。 我们推导了在圆偏振微波辐照下，由FMI中的自旋运动在NM层中引起的交流和直流自旋电流。 如果我们将自旋运动视为经典，交流自旋电流可以表示出来。 另一方面，如果我们将自旋运动视为量子准粒子，就可以推导出直流自旋电流。 在这些推导之后，虽然评估自旋电流的计算成本非常高，但我们使用Quantics张量交叉插值（QTCI）方法来缓解这一问题。 我们展示了自旋电流随温度、微波频率和超导层厚度变化的数值结果。 值得注意的是，交流和直流自旋电流的温度依赖性表现出相干峰。 此外，我们在自旋电流与超导层厚度的依赖关系中发现了一个转变结构，在特定频率之后，这种依赖关系发生了变化。 显示英文摘要

摘要： Spin pumping with superconductors has been extensively studied, particularly in double-layer systems. In this study, we investigate spin pumping in a trilayer system comprising a ferromagnetic insulator (FMI), a superconductor (SC), and a normal metal (NM). We derive the AC and DC spin currents in the NM layer induced by spin motion in the FMI under circularly polarized microwave irradiation. If we treat the spin motion as classical, the AC spin current is expressed. On the other hand, if we treat the spin motion as quantum quasiparticles, the DC spin current is derived. After these derivations, while the computational cost of evaluating the spin current is extremely high, we mitigate this using the Quantics Tensor Cross Interpolation (QTCI) method. We present numerical results showing the dependence of the spin current on temperature, microwave frequency, and superconductor layer thickness. Notably, the temperature dependence of AC and DC spin currents exhibits a coherence peak. Furthermore, we have discovered a transition structure in the dependence of the spin current on the thickness of the superconductor layer, where the dependence changes after a particular frequency.