标题： 拓扑超导体/铁磁绝缘体异质结构中的混合集体激发 显示英文标题

标题： Hybrid collective excitations in topological superconductor/ferromagnetic insulator heterostructures

摘要： 我们为拓扑超导体/铁磁绝缘体(TS/FI)混合结构中的动态邻近效应发展了一种线性响应理论。 我们的方法结合了TS中电子格林函数的非平衡准经典Keldysh-Usadel方程与控制FI中磁化动力学的Landau-Lifshitz-Gilbert方程。 在这一框架下，我们研究了由邻近效应引起的自旋波与超导集体激发之间的耦合。 我们发现TS表面态固有的自旋-动量锁定导致超导Nambu-Goldstone(相位)集体模与自旋波之间的杂化，从而产生了复合自旋波-Nambu-Goldstone激发。 通过分析和数值方法分析了耦合强度相对于相关物理参数的依赖关系。 相反，我们表明Higgs(振幅)模在一级近似下不与自旋波耦合，因此不参与杂化集体激发的形成。 显示英文摘要

摘要： We develop a linear response theory for the dynamical proximity effect in topological superconductor/ferromagnetic insulator (TS/FI) hybrid structures. Our approach combines the nonequilibrium quasiclassical Keldysh-Usadel equations for the electronic Green's functions in the TS with the Landau-Lifshitz-Gilbert equation governing the magnetization dynamics in the FI. Within this framework, we study the proximity-induced coupling between magnons and superconducting collective excitations. We find that the spin-momentum locking intrinsic to the surface state of the TS leads to a hybridization between the superconducting Nambu-Goldstone (phase) collective mode and magnons, resulting in the emergence of composite magnon-Nambu-Goldstone excitations. The dependence of the coupling strength on relevant physical parameters is analyzed both analytically and numerically. In contrast, we show that the Higgs (amplitude) mode does not couple to magnons at linear order and therefore does not participate in the formation of hybrid collective excitations.