Energy spectrum and persistent current in an armchair hexagonal graphene ring in the presence of vacancies, Rashba and Zeeman interactions

Abstract

The effects of random vacancies, Rashba and Zeeman interactions on the energy spectrum and persistent current in an armchair hexagonal graphene ring are investigated. It is found that in the absence of Rashba and Zeeman interactions, both the inner and outer radii of an ordered graphene ring are the two dominant parameters in determining the value of the persistent current. Furthermore, zero energy modes resulting from vacancies increase the persistent current independent of the number of carbon atoms or Rashba and Zeeman interactions. However, Rashba and Zeeman interactions significantly decrease the persistent current in an ordered armchair hexagonal graphene ring. Therefore, by creating artificial vacancies, we can compensate for the negative effect of Rashba and Zeeman interactions on the persistent current.