Structure Dependence of Excitonic Effects in Chiral Graphene Nanoribbons  

作　　者：吕燕 吕文刚 王立 

机构地区：[1]Department of Physics,Nanehang University,Nanchang 330031 [2]Beijing National Laboratory for Condensed Matter Physics,and Institute of Physics,Chinese Academy of Sciences,Beijing 100190 [3]Beijing Key Laboratory for Nanomaterials and Nanodevices,Beijing 100190

出　　处：《Chinese Physics Letters》2017年第1期102-106,共5页中国物理快报（英文版）

基　　金：Supported by the National Key Scientific Research Projects of China under Grant No 2015CB932400;the National Natural Science Foundation of China under Grant Nos 11504158,61474059,and U1432129;the Program for New Century Excellent Talents in University of Ministry of Education of China under Grant No NCET-11-1003;the Jiangxi Provincial'Ganpo Talentes 555Projects'

摘　　要：We explore the excitonic effects in chiral graphene nanoribbons (cGNRs), whose edges are composed alternatively of armchair-edged and zigzag-edged segments. For cGNRs dominated by armchair edges, their energy gaps and exciton energies decrease with increasing chirality angles, and they, as functions of widths, oscillate with the period of three, while the exciton binding energies do not have such distinct oscillation. On the other hand, for cGNRs dominated by zigzag edges, all the energy gaps, exciton energies, and exciton binding energies show oscillation properties with their widths, due to the interactions between the edge states localized at the opposite zigzag edges. In addition, the triplet excitons are energy degenerate when the electrons are spin-unpolarized, while the degeneracy split when the electrons are spin-polarized. All the studied cGNRs show strong excitonic effects with the exciton binding energies of hundreds of meV.We explore the excitonic effects in chiral graphene nanoribbons (cGNRs), whose edges are composed alternatively of armchair-edged and zigzag-edged segments. For cGNRs dominated by armchair edges, their energy gaps and exciton energies decrease with increasing chirality angles, and they, as functions of widths, oscillate with the period of three, while the exciton binding energies do not have such distinct oscillation. On the other hand, for cGNRs dominated by zigzag edges, all the energy gaps, exciton energies, and exciton binding energies show oscillation properties with their widths, due to the interactions between the edge states localized at the opposite zigzag edges. In addition, the triplet excitons are energy degenerate when the electrons are spin-unpolarized, while the degeneracy split when the electrons are spin-polarized. All the studied cGNRs show strong excitonic effects with the exciton binding energies of hundreds of meV.

关 键 词：Structure Dependence of Excitonic Effects in Chiral Graphene Nanoribbons 

分 类 号：O613.71[理学—无机化学] TB383.1[理学—化学]