线缺陷对扶手型石墨烯纳米带能隙的调控  

Tunable Energy Gap Controlled by a Line Defect in Armchair Graphene Nanoribbons

作　　者：刘丽丽[1] 龙文[1] 

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）》2016年第1期20-26,29,共8页Journal of Capital Normal University：Natural Science Edition

基　　金：国家自然科学基金(11074174)

摘　　要：采用单轨道最近邻紧束缚模型,我们研究了线缺陷的位置、类型和强度对扶手型石墨烯纳米带(AGNRs)能隙的调控.计算结果表明,对于带宽N为3n(n为整数)的半导体AGNRs,加一条位于Ni≠3m-1的两体线缺陷后(N_i为缺陷位置,m为整数),能隙关闭,纳米带呈金属性;而N=3n+1的半导体AGNRs关闭能隙的两体线缺陷位置为Ni≠3m-2.对于带宽N=3n+2的金属性AGNRs,可在Ni≠3m位置处加一条子格线缺陷打开能隙,使纳米带呈半导体性,同时在费米能附近出现一个波速为零的局域态;增加正常原子与缺陷原子之间的交叠积分,可使局域态消失,同时保持半导体性.利用格林函数方法,我们研究了一个两端口有限尺寸AGNRs的电子输运模型,计算了体系在有线缺陷时的透射系数和态密度,结果与能带谱计算结果相一致.A single-orbital nearest-neighbor tight-binding model is used to study the role of line defects on the energy gap in armchair graphene nanoribbons. In a metallic ribbon, an energy gap may open up if a sublattice line defect is introduced. Moreover, a new state with zero velocity may emerge when the ordinary-defect hopping term is weaker. In a semiconducting ribbon, the energy gap may disappear if a dimer line defect is located in any position except some definite lines, for the case of N = 3n the definite position is Ni = 3m - 1, for the case of N = 3n ＋ 1 the definite position is Ni =3n-2 （n and m are integers, and N is the width of ribbon）.

关 键 词：扶手型石墨烯纳米带 线缺陷 能隙. 

分 类 号：O469[理学—凝聚态物理]