中国物理B ›› 2010, Vol. 19 ›› Issue (11): 117105-117106.doi: 10.1088/1674-1056/19/11/117105

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The complex band structure for armchair graphene nanoribbons

张留军, 夏同生   

  1. School of Electronic Information Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
  • 收稿日期:2010-05-20 修回日期:2010-05-28 出版日期:2010-11-15 发布日期:2010-11-15
  • 基金资助:
    Project supported by the Fundamental Research Funds for the Central Universities (Grant No. YWF-10-02-040).

The complex band structure for armchair graphene nanoribbons

Zhang Liu-Jun(张留军) and Xia Tong-Sheng(夏同生)   

  1. School of Electronic Information Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
  • Received:2010-05-20 Revised:2010-05-28 Online:2010-11-15 Published:2010-11-15
  • Supported by:
    Project supported by the Fundamental Research Funds for the Central Universities (Grant No. YWF-10-02-040).

摘要: Using a tight binding transfer matrix method, we calculate the complex band structure of armchair graphene nanoribbons. The real part of the complex band structure calculated by the transfer matrix method fits well with the bulk band structure calculated by a Hermitian matrix. The complex band structure gives extra information on carrier's decay behaviour. The imaginary loop connects the conduction and valence band, and can profoundly affect the characteristics of nanoscale electronic device made with graphene nanoribbons. In this work, the complex band structure calculation includes not only the first nearest neighbour interaction, but also the effects of edge bond relaxation and the third nearest neighbour interaction. The band gap is classified into three classes. Due to the edge bond relaxation and the third nearest neighbour interaction term, it opens a band gap for N=3M-1. The band gap is almost unchanged for N=3M+1, but decreased for N=3M. The maximum imaginary wave vector length provides additional information about the electrical characteristics of graphene nanoribbons, and is also classified into three classes.

Abstract: Using a tight binding transfer matrix method, we calculate the complex band structure of armchair graphene nanoribbons. The real part of the complex band structure calculated by the transfer matrix method fits well with the bulk band structure calculated by a Hermitian matrix. The complex band structure gives extra information on carrier's decay behaviour. The imaginary loop connects the conduction and valence band, and can profoundly affect the characteristics of nanoscale electronic device made with graphene nanoribbons. In this work, the complex band structure calculation includes not only the first nearest neighbour interaction, but also the effects of edge bond relaxation and the third nearest neighbour interaction. The band gap is classified into three classes. Due to the edge bond relaxation and the third nearest neighbour interaction term, it opens a band gap for N=3M-1. The band gap is almost unchanged for N=3M+1, but decreased for N=3M. The maximum imaginary wave vector length provides additional information about the electrical characteristics of graphene nanoribbons, and is also classified into three classes.

Key words: armchair graphene nanoribbons, complex band structure, edge bond relaxation, third nearest neighbour interaction

中图分类号:  (Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.))

  • 71.15.Ap
73.22.-f (Electronic structure of nanoscale materials and related systems)