Nonreciprocal propagation of surface waves in quasiperiodic superlattices

We investigate the dispersion relations and amplitude profiles of magnetoplasmons in semi-infinite superlattices, the unit cells of which are composed of two different thicknesses of bilayer minicells arranged in a Fibonacci sequence. We find that there exists another spectrum of both bulk and surface modes in the quasiperiodic structure, which is not present in the periodic structure. These surface modes become nonreciprocal with respect to the direction of propagation in an applied magnetic field. Since the number and frequency of these modes depend upon the layering of the unit cell, and since the surface modes are nonreciprocal, our results could be important to surface-wave-device applications.