锯齿型石墨烯纳米带的能带研究  

Band structures of zigzag graphene nanoribbons

作　　者：王雪梅[1] 刘红[1] 

机构地区：[1]南京师范大学物理科学与技术学院,南京210046

出　　处：《物理学报》2011年第4期547-556,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10947004);江苏省自然科学基金(批准号:BK2008427);高校博士学科点专项基金(批准号:200803190004)资助的课题~~

摘　　要：运用π电子紧束缚模型,具体研究了锯齿型石墨烯纳米带(ZGNRs)的边界结构对能带,特别是费米面附近的导带和价带电子的影响.计算了七种不同边界结构的ZGNRs的能带色散关系及费米面附近价带电子在原胞中各原子上的分布情况.计算结果表明:两边界都无悬挂原子的NN-ZGNRs,只有一边界有悬挂原子的DN-ZGNRs,两边界都有五边形环的SPP-ZGNRs和ASPP-ZGNRs为金属性.两边界都有悬挂原子的DD-ZGNRs,一边界为五边形环另一边界无悬挂原子的PN-ZGNRs和一边界为五边形环另一边界有悬挂原子的PD-ZGNRs都为半导体性,但是随纳米带宽度的增加,DD-ZGNRs和PD-ZGNRs的带隙很快减小至零,而PN-ZGNRs的带隙随宽度呈指数衰减至一个有限值0.154eV.结果也显示出不同边界结构对费米面附近价带上电子分布产生的影响不同,在石墨烯边界原子上电子概率都相对较高.Based on the π-electron tight-binding model,for zigzag graphene nanoribbons（ZGNRs） the influence of boundary structure on band structure,specially the electrons of the valence band and the conductor band near the Fermi level,are studied in detail.We investigate the band structures and the distributions of electrons of different atoms in a unit cell of the valence band near the Fermi level of ZGNRs with seven reasonable boundary structures.We find NN-ZGNRs with no dangling atoms on both edges,DN-ZGNRs with dangling atoms only on one edge,SPP-ZGNRs and ASPP-ZGNRs each with pentagons on both two edges and being metallic,DD-ZGNRs with dangling atoms on both two edges,PN-ZGNRs each with a defective structure of pentagons on one edge and no dangling atoms on the other edge,PD-ZGNRs with a pentagon on one edge and dangling atoms on the other edge being semiconducting,and the energy gap being inversely proportional to the width of nanoribbons.But for DD-ZGNRs and PD-ZGNRs,the energy gaps quickly reduce to zero with the increase of width;for PN-ZGNRs,the energy gaps decrease exponentially to a limited value of 0.154 eV.It is found that different boundary structures have different effects on the distribution of electrons in the valence band near the Fermi level.And the probability for electrons staying in the atoms on two edges of nanoribbons is relatively large.

关 键 词：锯齿型石墨烯纳米带 紧束缚模型 电子密度分布 缺陷结构 

分 类 号：O481.1[理学—固体物理]