外加横向电场作用下石墨烯纳米带电子结构的密度泛函紧束缚计算  

Electronic structure of graphene nanoribbons under external electric field by density functional tight binding

作　　者：崔洋 李静 张林 Cui Yang;Li Jing;Zhang Lin(Key Laboratory for Anisotropy and Texture of Materials,Northeastern University,Shenyang 110819,China;The State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学,材料各向异性与织构教育部重点实验室,沈阳110819 [2]东北大学,轧钢国家重点实验室,沈阳110819 [3]东北大学材料科学与工程学院,沈阳110819

出　　处：《物理学报》2021年第5期90-97,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51671051);国家重点研发计划(批准号:2016YFB0701304)资助的课题.

摘　　要：采用基于密度泛函理论的紧束缚方法计算研究了外加横向电场对边缘未加氢/加氢钝化的扶手椅型石墨烯纳米带的电子结构及电子布居数的影响.计算结果表明,石墨烯纳米带的能隙变化受其宽带影响.当施加沿其宽度方向的横向外加电场时,纳米带的能带结构及态密度都会产生较大的变化.对于具有半导体性的边缘未加氢纳米带,随着所施加电场强度的增加,会发生半导体-金属的转变.同时,电场也会对能级分布产生显著影响.外加电场导致纳米带内原子上电子布居数分布失去对称性,电场强度越大,其布居数不对称性越明显.边缘加氢钝化可以显著改变纳米带内原子上的布居数分布.In recent years,the rapid development of electronic information technology has brought tremendous convenience to people’s lives,and the devices used have become increasingly miniaturized.However,due to the constraints of the process and the material itself,as the size of the devices made of silicon materials is further reduced,obvious short channel effects and dielectric tunneling effects will appear,which will affect the normal operations of these devices.In order to overcome this development bottleneck,it is urgent to find new materials for the devices that can replace silicon.Carbon has the same outer valence electron structure as silicon.Since 2004,Geim[Novoselov K S,Geim A K,Morozov S V,et al.2005 Nature 438197]prepared two-dimensional graphene with a honeycomb-like planar structure formed by sp^(2) hybridization,graphene has received extensive attention from researchers and industrial circles for its excellent electronic and mechanical properties.However,graphene is not a true semiconductor,and it has no band gap in its natural state.The energy gap can be opened by preparing graphene nanoribbons.On this basis,the electronic structure of the nanoribbons can be further controlled by using an external electric field to destroy the symmetric structure of the nanoribbons.In this paper,the tight-binding method based on density functional theory is used to calculate and study the influence of external transverse electric field on the electronic structure and electron population of unhydrogenated/hydrogenated armchair graphene nanoribbons.The calculation results show that whether there is hydrogen on the edge of the graphene nanoribbons or not,the energy gap changed at theГpoint shows a three-group periodic oscillation decreasing law,and as N increases,the energy gap will disappear.Under the external electric field,the band structure and the density of states of the nanoribbons will change greatly.For un-hydrogenated nanoribbons with semiconducting properties,as the intensity of the external electric field incre

关 键 词：石墨烯 纳米带 电子结构 外电场 

分 类 号：TQ127.11[化学工程—无机化工] TB383.1[一般工业技术—材料科学与工程]