中国物理B ›› 2016, Vol. 25 ›› Issue (6): 68105-068105.doi: 10.1088/1674-1056/25/6/068105

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Bound states of Dirac fermions in monolayer gapped graphene in the presence of local perturbations

Mohsen Yarmohammadi, Malek Zareyan   

  1. 1 Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran;
    2 Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45195-1159, Iran
  • 收稿日期:2015-12-10 修回日期:2016-02-05 出版日期:2016-06-05 发布日期:2016-06-05
  • 通讯作者: Mohsen Yarmohammadi E-mail:m.yarmohammadi69@gmail.com

Bound states of Dirac fermions in monolayer gapped graphene in the presence of local perturbations

Mohsen Yarmohammadi1, Malek Zareyan2   

  1. 1 Young Researchers and Elite Club, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran;
    2 Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, 45195-1159, Iran
  • Received:2015-12-10 Revised:2016-02-05 Online:2016-06-05 Published:2016-06-05
  • Contact: Mohsen Yarmohammadi E-mail:m.yarmohammadi69@gmail.com

摘要:

In graphene, conductance electrons behave as massless relativistic particles and obey an analogue of the Dirac equation in two dimensions with a chiral nature. For this reason, the bounding of electrons in graphene in the form of geometries of quantum dots is impossible. In gapless graphene, due to its unique electronic band structure, there is a minimal conductivity at Dirac points, that is, in the limit of zero doping. This creates a problem for using such a highly motivated new material in electronic devices. One of the ways to overcome this problem is the creation of a band gap in the graphene band structure, which is made by inversion symmetry breaking (symmetry of sublattices). We investigate the confined states of the massless Dirac fermions in an impured graphene by the short-range perturbations for “local chemical potential” and “local gap”. The calculated energy spectrum exhibits quite different features with and without the perturbations. A characteristic equation for bound states (BSs) has been obtained. It is surprisingly found that the relation between the radial functions of sublattices wave functions, i.e., fm+(r), gm+(r), and fm-(r), gm-(r), can be established by SO(2) group.

关键词: monolayer gapped graphene, quantum dots, bound states, inversion symmetry breaking

Abstract:

In graphene, conductance electrons behave as massless relativistic particles and obey an analogue of the Dirac equation in two dimensions with a chiral nature. For this reason, the bounding of electrons in graphene in the form of geometries of quantum dots is impossible. In gapless graphene, due to its unique electronic band structure, there is a minimal conductivity at Dirac points, that is, in the limit of zero doping. This creates a problem for using such a highly motivated new material in electronic devices. One of the ways to overcome this problem is the creation of a band gap in the graphene band structure, which is made by inversion symmetry breaking (symmetry of sublattices). We investigate the confined states of the massless Dirac fermions in an impured graphene by the short-range perturbations for “local chemical potential” and “local gap”. The calculated energy spectrum exhibits quite different features with and without the perturbations. A characteristic equation for bound states (BSs) has been obtained. It is surprisingly found that the relation between the radial functions of sublattices wave functions, i.e., fm+(r), gm+(r), and fm-(r), gm-(r), can be established by SO(2) group.

Key words: monolayer gapped graphene, quantum dots, bound states, inversion symmetry breaking

中图分类号:  (Electrical and magnetic properties related to treatment conditions)

  • 81.40.Rs
72.10.Bg (General formulation of transport theory) 72.10.Fk (Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect))