线缺陷对锯齿型石墨烯带能谱和边态的调控

Tunable Energy Spectrum and Edge States by Line Defects in Zigzag Graphene Nanoribbons

研究了边界线缺陷对锯齿型石墨烯带能谱和边态的调控.利用紧束缚模型和格林函数方法,我们计算了石墨烯带的色散关系、局域态密度、电导和格点波函数.数值计算结果表明边界线缺陷占位能不仅能连续调控费米面附近平带部分的色散关系,而且能将原来的双侧边态调控为单侧边态量子通道.线缺陷的交叠积分可连续调控导带底弯带部分的色散关系,使电子更集中地占据单侧边态.导带底在第一布里渊区边界的边态对线缺陷有鲁棒性.

The role of line defects on the energy bands and edge states was studied in zigzag graphene nanoribbons. The dispersion relation,the local density of state,the conductance and the wave function were calculated by the tightbinding model and Green＇s function method. The results indicated that the on-site energy of line defects sites can continuously change the dispersion relation of the flat band near the Fermi level,and edge states located on twosided boundaries can be tuned into one-sided edge sites. Furthermore,the dispersion relation of the curve part of the bottom conduction band can be controlled by the hopping term of line defects. The edge state of the lowest conduction band at the boundary of the first Brillouin zone was robust at the presence of edge line defects.