Khang Nguyen Huynh Duy, Nakano Soichiro, Shirokura Takanori, Miyamoto Yasuyoshi, Hai Pham Nam
Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo, 152-8550, Japan.
Department of Physics, Ho Chi Minh City University of Education, 280 An Duong Vuong Street, District 5, Ho Chi Minh City, 738242, Vietnam.
Sci Rep. 2020 Jul 22;10(1):12185. doi: 10.1038/s41598-020-69027-6.
The large spin Hall effect in topological insulators (TIs) is very attractive for ultralow-power spintronic devices. However, evaluation of the spin Hall angle and spin-orbit torque (SOT) of TIs is usually performed on high-quality single-crystalline TI thin films grown on dedicated III-V semiconductor substrates. Here, we report on room-temperature ultralow power SOT magnetization switching of a ferrimagnetic layer by non-epitaxial BiSb TI thin films deposited on Si/SiO substrates. We show that non-epitaxial BiSb thin films outperform heavy metals and other epitaxial TI thin films in terms of the effective spin Hall angle and switching current density by one to nearly two orders of magnitude. The critical SOT switching current density in BiSb is as low as 7 × 10 A/cm at room temperature. The robustness of BiSb against crystal defects demonstrate its potential applications to SOT-based spintronic devices.
拓扑绝缘体（TIs）中的大自旋霍尔效应对于超低功耗自旋电子器件极具吸引力。然而，对拓扑绝缘体的自旋霍尔角和自旋轨道矩（SOT）的评估通常是在生长于专用III-V族半导体衬底上的高质量单晶TI薄膜上进行的。在此，我们报告了通过沉积在Si/SiO衬底上的非外延BiSb TI薄膜实现的室温下铁磁层的超低功耗SOT磁化翻转。我们表明，非外延BiSb薄膜在有效自旋霍尔角和开关电流密度方面比重金属和其他外延TI薄膜高出一到近两个数量级。BiSb中的临界SOT开关电流密度在室温下低至7×10 A/cm。BiSb对晶体缺陷的鲁棒性证明了其在基于SOT的自旋电子器件中的潜在应用。
