• 文献标题:   Equilibrium currents in a Corbino graphene ring
  • 文献类型:   Article
  • 作  者:   LOPEZ A, BOLIVAR N, MEDINA E, BERCHE B
  • 作者关键词:   tightbinding hamiltonian, graphene, spinorbit interaction, charge spin transport
  • 出版物名称:   CONDENSED MATTER PHYSICS
  • ISSN:   1607-324X EI 2224-9079
  • 通讯作者地址:   Inst Venezolano Invest Cient
  • 被引频次:   0
  • DOI:   10.5488/CMP.17.33803
  • 出版年:   2014

▎ 摘  要

We address the description of a graphene Corbino disk in the context of a tight binding approach that includes both kinetic and Rashba spin-orbit coupling due to an external out-of-plane electric field. Persistent equilibrium currents are induced by an external magnetic field breaking time reversal symmetry. By direct diagonalization, we compute the spectrum and focus on the dispersion near the K points at the Fermi level. The dispersion keenly reproduces that of a continuum model in spite of the complexity of the boundary conditions. We validate the assumptions of the continuum model in terms of predominant zig-zag boundaries conditions and weak sub-band coupling. The wave functions displaying the lowest transverse modes are obtained, showing the predominance of edge states with charge density at the zig-zag edges. The persistent charge currents, nevertheless, do not follow the traditional argument of current cancellation from levels below the Fermi level, and thus they depart in the tight-binding from those found in the continuum model.