Tunneling in the Brillouin zone: Theory of backscattering in valley Hall edge channels

Abstract

In many time-reversal-symmetric implementations of topological transport of classical waves, backscattering is nominally forbidden only within a description that does not include large momentum transfer. Here, the authors introduce a more refined picture, in which backscattering is induced by tunneling transitions in the reciprocal (quasimomentum) space. They predict enhanced backscattering at discrete centers, whose locations depend both on the energy and the local slope of the domain wall. The theory provides guidance to the design of future topological devices with reduced backscattering.

Topics & Concepts