• 文献标题:   Topological phase transition in a graphene system with a coexistence of Coulomb interaction, staggered potential, and intrinsic spin-orbit coupling
  • 文献类型:   Article
  • 作  者:   CAO J, XIONG SJ
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121
  • 通讯作者地址:   Nanjing Univ
  • 被引频次:   7
  • DOI:   10.1103/PhysRevB.88.085409
  • 出版年:   2013

▎ 摘  要

Using a mean-field approximation of the Hubbard model, we investigate the topological phase transition of the graphene system with an intrinsic spin-orbit coupling undergoing a coexistence of a Coulomb interaction and a staggered potential. We find that in an infinite system the antiferromagnetic phase can be classified into four types according to their topological properties: Two of them belong to the normal band-insulator phase, the third type is the quantum spin Hall insulator phase, although the inversion symmetry and the time-reversal symmetry are broken, and the fourth is the spin-polarized quantum Hall insulator phase, a different state of matter possessing Chern number 1 and spin Chern numbers 1/2, which emerges due to the interplay between the Coulomb repulsion and the breaking of the sublattice symmetry. In addition, the number of edge states in a zigzag graphene ribbon whose parameters belong to one of these types confirms the validity of the analysis of the four phases. All the results obtained from a simplified toy model agree with those acquired from the self-consistent calculation. This indicates that the proposed toy model can exactly and analytically provide the essential information on the phase transition process of such graphene systems.