An electromagnetic scattering approach to identifying topological and non-topological unidirectional edge states at gyrotropic plasma interfaces

Abstract

We present an approach to identifying topological edge states in two dimensional (2D) problems. Such scattering-immune surface waves are typically identified using the Berry concept, which evaluates Chern numbers of bulk transmission bands. Instead, here, we approach the task from an analytical electromagnetic scattering perspective, which enables the study of a wide class of configurations in which waves are confined to propagate at the interface between a topologically non-trivial magnetized plasma and a topologically trivial medium such as air. Although it is of theoretical significance to classify interfacial states by their topological invariants, we believe that this approach enables the engagement of a broader range of researchers, particularly experimentalists who seek to design devices that exploit the ensuing non-reciprocal and scattering-immune properties.