Emergence of anisotropic Gilbert damping in ultrathin Fe layers on GaAs(001)
Emergence of anisotropic Gilbert damping in ultrathin Fe layers on GaAs(001)
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DOI：
10.1038/s41567-018-0053-8
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发表时间：
2018-05-01
期刊：
影响因子：
19.6
通讯作者：
Back, C. H.
中科院分区：
文献类型：
--
作者：
Chen, L.;Mankovsky, S.;Back, C. H.
作为磁学中的一个基本参数，现象学的吉尔伯特阻尼常数α决定了许多自旋电子器件的性能。对于大多数磁性材料，α被视为进入Landau-Lifshitz-吉尔伯特方程的各向同性参数。然而，吉尔伯特阻尼会是各向异性的吗？虽然一些理论方法已经表明，各向异性α可以出现在单晶体系统，它的存在的实验证据是稀缺的。在这里，我们报告的各向异性磁阻尼的出现，通过探索准二维单晶铁磁金属/半导体界面，即Fe/GaAs（001）异质结。所观察到的各向异性阻尼显示双重C-2 v对称性，这是从界面Rashba和Dresselhaus自旋轨道相互作用的相互作用预期的，并且通过Fe/GaAs（001）界面处的各向异性态密度来体现。各向异性阻尼的这一发现将丰富磁化弛豫机制的理解，并可以提供一条通往其他铁磁金属/半导体界面的各向异性阻尼的搜索路线。
As a fundamental parameter in magnetism, the phenomenological Gilbert damping constant a determines the performance of many spintronic devices. For most magnetic materials, a is treated as an isotropic parameter entering the Landau-Lifshitz-Gilbert equation. However, could the Gilbert damping be anisotropic? Although several theoretical approaches have suggested that anisotropic a could appear in single-crystalline bulk systems, experimental evidence of its existence is scarce. Here, we report the emergence of anisotropic magnetic damping by exploring a quasi-two-dimensional single-crystalline ferromagnetic metal/semiconductor interface-that is, a Fe/GaAs(001) heterojunction. The observed anisotropic damping shows twofold C-2v symmetry, which is expected from the interplay of interfacial Rashba and Dresselhaus spin-orbit interaction, and is manifested by the anisotropic density of states at the Fe/GaAs (001) interface. This discovery of anisotropic damping will enrich the understanding of magnetization relaxation mechanisms and can provide a route towards the search for anisotropic damping at other ferromagnetic metal/semiconductor interfaces.