Current-induced nonreciprocity and refraction-free propagation in a one-dimensional graphene-based photonic crystal

Nonreciprocal photonic devices play a significant role in regulating the propagation of electromagnetic waves. Here we theoretically investigate the nonreciprocal properties of transverse magnetic modes in a one-dimensional graphene-based photonic crystal subjected to an applied electrical DC bias. We find that drifting electrons driven by the external DC electric field can give rise to extremely asymmetric dispersion diagrams. Furthermore, when the drifting electrons travel antiparallel to the normal component of the incident wave vector, the negative refraction is strongly suppressed, causing the energy of light to flow along the direction of the direct electric current. Our theoretical findings can be used to design nonreciprocal nanophotonic devices and enable light to propagate without refraction.