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arXiv 2210.02810cond-mat.supr-concond-mat.str-el
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直接探测 STO 上 FeSe 超导单层中的大自旋-轨道耦合：非平凡拓扑态的证据

Direct probing of a large spin-orbit coupling in the FeSe superconducting monolayer on STO: Evidence for nontrivial topological states

Khalil Zakeri, Dominik Rau, Jasmin Jandke, Fang Yang, Wulf Wulfhekel, Christophe Berthod

备注：
15 pages, 4 figures. arXiv admin note: text overlap with arXiv:2210.02058
发表信息：
ACS Nano 17, 9575 (2023)
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AI总结：

通过高分辨率自旋分辨光谱实验，发现STO上FeSe超导单层存在强自旋-轨道耦合，该强耦合可导致拓扑态形成并对高温超导机制至关重要。

摘要：

在凝聚态物理学中，自旋-轨道耦合（SOC）是一种基本的物理相互作用，它描述了电子自旋如何与其轨道运动耦合。它是固体中大量迷人现象的根源，例如物质的拓扑相、量子自旋霍尔态以及许多其他奇异的量子态。尽管在高温超导现象的大多数理论描述中 SOC 被忽略了，但原则上，引入这种相互作用可以修正这些化合物中超导性的微观图像。不仅导致 Cooper 配对的相互作用，而且序参量的对称性和相关态的拓扑特性都可以由 SOC 决定。在这里，通过以前所未有的分辨率进行能量、动量和自旋分辨的光谱实验，我们证明了，在用慢电子探测钛酸锶上的 FeSe 单层（一种原型二维高温超导体）的动态电荷响应时，散射截面表现出相当大的自旋不对称性。我们通过开发一个考虑了 SOC 的模型，揭示了观察到的自旋不对称性的起源。我们的分析表明，这种二维超导体中的 SOC 相当强。我们预计，如此强的 SOC 会对电子结构产生一些严重后果，并可能导致拓扑态的形成。此外，相当大的 SOC 可以与其他配对情景竞争，并且对高温超导的机制至关重要。

英文摘要：

In condensed-matter physics spin-orbit coupling (SOC) is a fundamental physical interaction, which describes how the electrons' spin couples to their orbital motion. It is the source of a vast variety of fascinating phenomena in solids such as topological phases of matter, quantum spin Hall states, and many other exotic quantum states. Although in most theoretical descriptions of the phenomenon of high-temperature superconductivity SOC has been neglected, including this interaction can, in principle, revise the microscopic picture of superconductivity in these compounds. Not only the interaction leading to Cooper pairing but also the symmetry of the order parameter and the topological character of the involved states can be determined by SOC. Here by preforming energy-, momentum-, and spin-resolved spectroscopy experiments with an unprecedented resolution we demonstrate that while probing the dynamic charge response of the FeSe monolayer on strontium titanate, a prototype two dimensional high-temperature superconductor using slow electrons, the scattering cross-section shows a considerable spin asymmetry. We unravel the origin of the observed spin asymmetry by developing a model in which SOC is taken into consideration. Our analysis indicates that SOC in this two dimensional superconductor is rather strong. We anticipate that such a strong SOC can have several serious consequences on the electronic structures and can lead to the formation of topological states. Moreover, a sizable SOC can compete with other pairing scenarios and is crucial for the mechanism of high-temperature superconductivity.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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