Dynamical superconducting states in hybrid structures superconductor/magnet

本项目将探索混合超导系统与量子电磁场（如光子和磁振子）的相互作用。这种相互作用强烈依赖于超导体中自旋三重态超导性、拓扑马约拉纳态或集体希格斯模式的存在，类似于粒子物理学中的希格斯玻色子。对这些系统的兴趣受到最近在超导体和铁磁绝缘体或金属的双层制造方面的进展的刺激，为各种现象提供了平台：拓扑超导态、耦合自旋、热和电荷输运或可由超导关联控制的自旋泵性质。不同有序电子系统之间的相互作用，例如超导体和磁体，在过去的几十年里，人们已经对其进行了深入的研究，但迄今为止，研究的重点一直是静态或低频特性。与此同时，微波量子技术和低温太赫兹光谱学的巨大进步要求理解动态超导邻近效应以及与动态模式的相互作用，例如光子，磁振子或超导序参量集体振荡。首先，我们讨论了动态超导邻近效应。在与磁有序材料接触时，非常规超导性在界面附近出现。一些突出的例子是三重态超导，非均匀相态（螺旋超导态）和拓扑超导。在自旋电子学领域中利用超导体/磁体混合结构意味着磁化的动力学特性。它包含了邻近诱导的非常规超导的动力学响应。然而，这种动态非常规超导的基本方面以及应用前景几乎没有调查，直到今天，我们正在计划填补这一空白。我们的工作计划包括研究自旋波和电磁辐射在超导/铁磁金属系统中产生的动力学三重态关联，以及S/F杂化系统中的非均匀相态对铁磁体中磁化动力学的响应。其次，我们重点研究了（反）铁磁绝缘体中拓扑Majorana模和集体Higgs模与磁振子的耦合。为了理解由超导体、电磁场和自旋波组成的混合量子系统的行为，所有这些效应都非常重要。为此，我们将学习如何控制超导邻近效应与光，工程师和探针马约拉纳状态和希格斯模式耦合磁振子。我们将深入了解超导混合系统的动力学性质，这些系统可能用于快速发展的量子技术。

This project will explore the interaction of hybrid superconducting systems with quantum electromagnetic fields such as photons and magnons. This interaction strongly depends on the presence of spin-triplet superconductivity, topological Majorana states or collective Higgs modes in a superconductor, analogous to the Higgs boson in particle physics. The interest in these systems is stimulated by the recent progress in the fabrication of bilayers of superconductors and ferromagnetic insulators or metals providing a platform for a wide range of phenomena: topological superconducting states, coupled spin, heat and charge transport or spin pumping properties controllable by superconducting correlations.Interactions between differently ordered electronic systems, such as superconductors and magnets, have been thoroughly investigated in the past decades, but the focus so far has been on static or low-frequency properties. Simultaneously, the enormous progress in microwave quantum technology and low-temperature terahertz spectroscopy calls for an understanding of dynamical superconducting proximity effects and the interplay with dynamical modes, such as photons, magnons or superconducting order parameter collective oscillations. That is the focus of our project.First, we address the dynamical superconducting proximity effect. In contact with a magnetically ordered material unconventional superconductivity emerges close to the interface. Some prominent examples are triplet superconductivity, inhomogeneous phase states (helical superconducting states) and topological superconductivity. Exploiting superconductor/magnet hybrid structures in the field of spintronics implies a dynamical character of the magnetization. It entails a dynamical response of the proximity-induced unconventional superconductivity. However, both the fundamental aspects as well as prospects for applications of such dynamical unconventional superconductivity are hardly investigated until today, and we are planning to fill this gap. Our work plan includes investigations of dynamical triplet correlations in superconductor/ferromagnetic metal systems generated by spin waves and electromagnetic radiation as well as the response of inhomogeneous phase states in S/F hybrids to the magnetization dynamics in ferromagnets.Second, we focus on the coupling of topological Majorana modes and collective Higgs modes with magnons in (anti)ferromagnetic insulators. All these effects are fundamentally important in order to understand the behaviour of hybrid quantum systems consisting of superconductors, electromagnetic fields and spin waves. To this end, we will learn how to control the superconducting proximity effect with light, engineer and probe Majorana states and Higgs modes coupled with magnons. With that we will gain a deep insight into the dynamical properties of superconducting hybrid systems which potentially can be used in the rapidly developing quantum technologies.