Giant Spin Pumping and Inverse Spin Hall Effect in the Presence of Surface and Bulk Spin-Orbit Coupling of Topological Insulator Bi2Se3
Giant Spin Pumping and Inverse Spin Hall Effect in the Presence of Surface and Bulk Spin-Orbit Coupling of Topological Insulator Bi2Se3
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DOI：
10.1021/acs.nanolett.5b03274
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发表时间：
2015-10-01
期刊：
影响因子：
10.8
通讯作者：
Wang, Jian-Ping
中科院分区：
文献类型：
--
作者：
Jamali, Mandi;Lee, Joon Sue;Wang, Jian-Ping
三维（3D）拓扑绝缘体因其强自旋轨道耦合（SOC）和自旋织构表面态的存在而闻名，这些表面态可能被用于“拓扑自旋电子学”。“在这里，我们使用自旋泵浦和逆自旋霍尔效应来证明在室温下从金属铁磁体（CoFeB）到原型3D拓扑绝缘体Bi 2Se 3的成功自旋注入。由金属铁磁体的磁化动力学驱动的自旋泵浦过程将自旋电流引入拓扑绝缘体层中，导致铁磁共振（FMR）线宽的加宽。通过Bi 2Se 3的表面的自旋泵浦的理论建模，以及测量的自旋-电荷转换信号的角度依赖性，表明泵浦的自旋电流首先大大增强的表面SOC，然后转换成直流电压信号，主要是由反自旋霍尔效应由于SOC的大块Bi 2Se 3。我们发现，FMR线的宽度显着变宽（超过5倍），我们推导出的Bi 2Se 3层的自旋霍尔角为0.43大。
Three-dimensional (3D) topological insulators are known for their strong spin-orbit coupling (SOC) and the existence of spin-textured surface states that might be potentially exploited for "topological spintronics." Here, we use spin pumping and the inverse spin Hall effect to demonstrate successful spin injection at room temperature from a metallic ferromagnet (CoFeB) into the prototypical 3D topological insulator Bi2Se3. The spin pumping process, driven by the magnetization dynamics of the metallic ferromagnet, introduces a spin current into the topological insulator layer, resulting in a broadening of the ferromagnetic resonance (FMR) line width. Theoretical modeling of spin pumping through the surface of Bi2Se3, as well as of the measured angular dependence of spin-charge conversion signal, suggests that pumped spin current is first greatly enhanced by the surface SOC and then converted into a dc-voltage signal primarily by the inverse spin Hall effect due to SOC of the bulk of Bi2Se3. We find that the FMR line width broadens significantly (more than a factor of 5) and we deduce a spin Hall angle as large as 0.43 in the Bi2Se3 layer.