自旋偏压驱动的硅烯和锗烯光控晶体管  

Optically controlled silicene and germanene transistors driven by spin-bias

作　　者：郑军[1] 马力[1] 李春雷[2] 袁瑞旸 郭亚涛 付旭日 Zheng Jun;Ma Li;Li Chun-Lei;Yuan Rui-Yang;Guo Ya-Tao;Fu Xu-Ri(College of Physics Science and Technology,Bohai University,Jinzhou 121013,China;College of Elementary Education,Capital Normal University,Beijing 100048,China;Department of Physics,Capital Normal University,Beijing 100048,China)

机构地区：[1]渤海大学物理科学与技术学院,锦州121013 [2]首都师范大学初等教育学院,北京100048 [3]首都师范大学物理系,北京100048

出　　处：《物理学报》2022年第19期355-362,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12174038);国家自然科学基金青年科学基金(批准号:11804236);辽宁省“兴辽英才”青年拔尖人才项目(批准号:XLYC2007141);北京市教育委员会科技计划面上项目(批准号:KM201810028022,KM201910028017)资助的课题。

摘　　要：基于二维拓扑绝缘体硅烯和锗烯,理论上提出了一种适用于自旋偏压的光控晶体管.利用非平衡格林函数方法,计算了非共振圆偏振光场对硅烯和锗烯晶体管输出电流的影响.研究表明,硅(锗)烯的拓扑性质与漏极电流的输出特性均受控于入射圆偏振光场的手征性和强度.硅烯晶体管在较弱的左旋圆偏振光场和自旋偏压的作用下,可对外输出纯自旋流和完全极化的自旋向上的电流.在强场的作用下,硅烯边缘态发生相变形成带隙,晶体管处于截止状态,对外输出电流几乎为零.有别于硅烯晶体管,锗烯晶体管在较弱光场辐照条件下可以获得稳定的纯自旋流,在强场的作用下对外输出100%极化的自旋向下的电流.通过对中心器件区域同时施加不同手性的圆偏振光,利用非共振偏振光场诱导的边缘态相变和局域光场引起的能带失配可使锗烯晶体管由开态转换到关态.硅烯和锗烯光控晶体管处于开态时自旋相关电流的输出极值几乎相等,但是锗烯光控晶体管的击穿电压相较于硅烯晶体管有显著提高,锗烯光控晶体管可以在更高的温度保持有效的工作状态.The transistor is the core unit of digital integrated circuits,and its performance and integration are the main determinants of chip performance.With the continuous progress of nano-manufacturing technology and process,high power and heat consumption have become a major problem restricting the development of integrated circuits.Using topological insulators instead of traditional semiconductors,and the spin and valley degrees of freedom instead of charge as information carriers,to design and fabricate transistors,and the use of optical interconnections to replace metal interconnections between functional units,are effective solutions of the thermal power consumption problem of nano-integrated circuits.Based on the two-dimensional topological insulators-silicene and germanene,we theoretically propose a kind of optically controlled transistor suitable for spin bias.The effects of off-resonant circularly polarized light on the output currents of silicene and germanene transistors are calculated by using the non-equilibrium Green’s function method.It is shown that the topological properties of silicene(germanene) and the output characteristics of drain current are controlled by the chirality and intensity of incident light.Under the coaction of weak left circularly polarized light and spin bias,the silicene transistors output pure spin current and fully polarized spin-up current.Under the action of strong field,the phase transition of the edge state of the silicene forms a band gap,the transistor is cut off,and the output current is almost zero.Different from the silicene transistor,the germanene transistor can obtain stable pure spin current under a weak light field,and output 100% polarized spin-down current under a strong field.By simultaneously applying off-resonant circularly polarized light of different chirality to the central device region,the germanene transistor can be turned off effectively by using the edge state phase transition induced by the polarized light field and the energy band mismatch caused by

关 键 词：光控晶体管 非共振圆偏振光 拓扑绝缘体 

分 类 号：O469[理学—凝聚态物理] TN32[理学—电子物理学]