Persistent currents in a graphene ring with armchair edges

Bor Luen Huang*, Ming Che Chang, Chung Yu Mou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


A graphene nanoribbon with armchair edges is known to have no edge state. However, if the nanoribbon is in the quantum spin Hall state, then there must be helical edge states. By folding a graphene ribbon into a ring and threading it by a magnetic flux, we study the persistent charge and spin currents in the tight-binding limit. It is found that, for a broad ribbon, the edge spin current approaches a finite value independent of the radius of the ring. For a narrow ribbon, inter-edge coupling between the edge states could open the Dirac gap and reduce the overall persistent currents. Furthermore, by enhancing the Rashba coupling, we find that the persistent spin current gradually reduces to zero at a critical value beyond which the graphene is no longer a quantum spin Hall insulator.

Original languageEnglish
Article number245304
JournalJournal of Physics Condensed Matter
Issue number24
Publication statusPublished - 2012 Jun 20

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics


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