Multi-pair nonreciprocal edge-states in one dimensional crystal based on Weyl semimetals

Abstract

This paper designs a one-dimensional nonreciprocal structure with a defect layer using magnetic Weyl Semimetals (WSMs). Unlike conventional optical crystal consisting of magnetic optical materials, WSMs as a topological material appear to have the property of time-reversal breaking, resulting in a large off-diagonal element in the permittivity without external magnetic fields. The energy band and transmission properties are studied based on the transfer matrix theory. It is revealed that multiple nonreciprocal dispersive curves corresponding to edge modes appear in the bandgap with different thicknesses of the defect layer. The results suggest that more pairs of nonreciprocal transmission peaks at a certain incident angle, providing a realistic and promising way to design multi-channel nonreciprocal transmission devices.