Giant Spin Pumping and Inverse Spin Hall Effect in the Presence of Surface and Bulk Spin鈭扥rbit Coupling of Topological Insulator Bi2Se3

详细信息    查看全文

• 作者：Mahdi Jamali ; Joon Sue Lee ; Jong Seok Jeong ; Farzad Mahfouzi ; Yang Lv ; Zhengyang Zhao ; Branislav K. Nikoli膰 ; K. Andre Mkhoyan ; Nitin Samarth ; Jian-Ping Wang
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：October 14, 2015
• 年：2015
• 卷：15
• 期：10
• 页码：7126-7132
• 全文大小：430K
• ISSN：1530-6992

文摘

Three-dimensional (3D) topological insulators are known for their strong spin鈥搊rbit coupling (SOC) and the existence of spin-textured surface states that might be potentially exploited for 鈥渢opological spintronics.鈥?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.