Nonreciprocal surface plasmons in angularly varying magnetized cylindrically rolled graphene

We analytically and numerically study the nonreciprocal surface waves guided by a magnetized graphene tube. When applying the magnetic bias perpendicularly to the cylinder axis, the conductivity profile cross section is nonuniform due to the varying angle between the magnetic bias and the surface-wave guiding tube, which enables us to obtain pronounced nonreciprocal modes with different field distributions for propagation in opposite directions due to the coupling between different values of orbital angular momentum. We show that this property can be leveraged for directional power delivery when changing the source location, and we study the isolation ratio as a function of different parameters. The dependence of the isolation ratio on the magnetic field bias allows simple, yet robust, control over the nonreciprocal wave propagation properties.