边缺陷诱导的双层锯齿型石墨烯纳米带能隙  

Edge-defect induced gaps in zigzag bilayer graphene nanoribbons

作　　者：韩超 龙文[1] HAN Chao;LONG Wen(Department of Physics,Capital Normal University,Beijing 100048)

机构地区：[1]首都师范大学物理系,北京100048

出　　处：《首都师范大学学报（自然科学版）》2022年第4期23-32,45,共11页Journal of Capital Normal University：Natural Science Edition

基　　金：国家自然科学基金面上项目(11074174)。

摘　　要：双层锯齿型石墨烯纳米带无能隙,不利于设计石墨烯场效应晶体管,边界线缺陷可打开能隙,使双边占据格点波函数变为单边占据,为设计双层石墨烯纳米器件提供理论支持.本文利用紧束缚模型,计算了双层锯齿型石墨烯纳米带能谱和格点波函数.数值计算表明,边界线缺陷层间跃迁可打开AA堆叠能隙,边界线缺陷占位能可打开AB堆叠能隙.双层锯齿型石墨烯纳米带的弱局域化行为与单层不同,缺陷占位能和层间跃迁可分别使双边占据的波函数变为单边占据,适当的缺陷占位能可使电子在上层(或下层)呈现优势占据.利用非平衡格林函数方法,研究了两端口有限尺寸双层锯齿型石墨烯纳米带的电子输运,计算了有边界线缺陷时体系的局域态密度和透射概率.Zigzag bilayer graphene nanoribbons are gapless,which is not good at the design of graphene field effect transistors. The edge line defects can open the band gap and the edge state localized on both sides may be tuned on one side,which provides theoretical support for the design of bilayer graphene nanodevices. The energy spectrum and lattice wave function of bilayer zigzag graphene nanoribbons are calculated by using the tight-binding model. The numerical results show that the hopping between edge line defects can open the AA stacking gap,and the on-site energy of edge line defects can open the AB stacking gap. The weak localization behavior in the bilayer zigzag graphene nanoribbons is different from that of single layer. The defect on-site energy and interlayer hopping can change the localized edge state,respectively. Appropriate defect on-site energy can make the electrons dominant in the upper layer(or lower layer). The electron transport of two-terminal bilayer zigzag graphene nanoribbons was investigated by using the non-equilibrium Green’s function method,and the local state density and transmission probability of the system with edge defect were calculated.

关 键 词：紧束缚模型 锯齿型 双层石墨烯纳米带 边态 能谱 

分 类 号：O411[理学—理论物理]