Elemental tin in the α-phase is an intriguing member of the family of topological quantum materials. In thin films, with decreasing thickness, α-Sn transforms from a 3D topological Dirac semimetal (TDS) to a 2D topological insulator (TI). Getting access to and making use of its topological surface states is challenging and requires interfacing to a magnetically ordered material. Herein, the successful epitaxial growth of α-Sn thin films on Co, forming the core of a spin-valve structure, is reported. Time- and element-selective ferromagnetic resonance experiments are conducted to investigate the presence of spin pumping through the spin-valve structure. A rigorous statistical analysis of the experimental data using a model based on the Landau–Lifshitz–Gilbert–Slonczewski equation is applied. A strong exchange coupling contribution is found, however no unambiguous proof for spin pumping. Nevertheless, the incorporation of α-Sn into a spin valve remains a promising approach given its simplicity as an elemental TI and its room-temperature application potential.

中文翻译：

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α-Sn薄膜自旋泵浦的研究

α 相中的元素锡是拓扑量子材料家族中的一个有趣的成员。在薄膜中，随着厚度的减小，α-Sn 从 3D 拓扑狄拉克半金属 (TDS) 转变为 2D 拓扑绝缘体 (TI)。访问和利用其拓扑表面状态具有挑战性，需要与磁性有序材料接口。在此，报道了在 Co 上成功外延生长 α-Sn 薄膜，形成自旋阀结构的核心。进行时间和元素选择性铁磁共振实验以研究通过自旋阀结构的自旋泵浦的存在。使用基于 Landau-Lifshitz-Gilbert-Slonczewski 方程的模型对实验数据进行严格的统计分析。发现强交换耦合贡献，然而，没有明确的证据证明自旋泵浦。尽管如此，考虑到 α-Sn 作为元素 TI 的简单性及其室温应用潜力，将 α-Sn 结合到自旋阀中仍然是一种很有前景的方法。