Controlling nonreciprocal surface states in magneto-optic photonic crystals by using monolayer graphene

Abstract We have theoretically investigated the nonreciprocal surface states created at the interface between the semi-infinite one-dimensional magneto-optic photonic crystal in Voigt configuration and air in the presence of monolayer graphene as a cap layer, using the transfer matrix method. The modification of surface states was studied by changing the Fermi energy of the graphene sheet. The results indicate that the nonreciprocality of surface states could be effectively controlled by Fermi energy. We also analyzed the effect of the termination layer of photonic crystal on surface states and found that the arrangement with termination layer of magnetized semiconductor supports unidirectional surface states.