Liu Xingchen, Tang Ning, Zhang Shixiong, Zhang Xiaoyue, Guan Hongming, Zhang Yunfan, Qian Xuan, Ji Yang, Ge Weikun, Shen Bo
State Key Laboratory of Artificial Microstructure and Mesoscopic Physics School of Physics Peking University Beijing 100871 China.
Frontiers Science Center for Nano-optoelectronics & Collaborative Innovation Center of Quantum Matter Peking University Beijing 100871 China.
Adv Sci (Weinh). 2020 Jun 1;7(13):1903400. doi: 10.1002/advs.201903400. eCollection 2020 Jul.
III-nitride wide bandgap semiconductors are favorable materials for developing room temperature spintronic devices. The effective manipulation of spin dynamics is a critical request to realize spin field-effect transistor (FET). In this work, the dependence of the spin relaxation time on external strain-induced polarization electric field is investigated in InGaN/GaN multiple quantum wells (MQWs) by time-resolved Kerr rotation spectroscopy. Owing to the almost canceled two different spin-orbit coupling (SOC), the spin relaxation time as long as 311 ps in the MQWs is obtained at room temperature, being much longer than that in bulk GaN. Furthermore, upon applying an external uniaxial strain, the spin relaxation time decreases sensitively, which originates from the breaking of the (2) symmetry. The extracted ratio of the SOC coefficients shows a linear dependence on the external strain, confirming the essential role of the polarization electric field. This effective manipulation of the spin relaxation time sheds light on GaN-based nonballistic spin FET working at room temperature.
III族氮化物宽带隙半导体是用于开发室温自旋电子器件的理想材料。对自旋动力学的有效操控是实现自旋场效应晶体管（FET）的关键要求。在这项工作中，通过时间分辨克尔旋转光谱研究了InGaN/GaN多量子阱（MQW）中自旋弛豫时间对外加应变诱导极化电场的依赖性。由于两种不同的自旋轨道耦合（SOC）几乎相互抵消，在室温下MQW中获得了长达311 ps的自旋弛豫时间，这比体GaN中的长得多。此外，施加外部单轴应变时，自旋弛豫时间敏感地减小，这源于（2）对称性的破坏。提取的SOC系数之比显示出对外加应变的线性依赖性，证实了极化电场的重要作用。这种对自旋弛豫时间的有效操控为室温下工作的基于GaN的非弹道自旋FET提供了思路。
