Fabry-Pérot resonant vortices and magnetoconductance in topological insulator constrictions with magnetic barriers

The edge states of two-dimensional time-reversal topological insulators support a perfect helical conductance on wide ribbons due to the absence backscattering. Here, we study changes in transport properties insulator nanoribbons by introducing constriction along ribbon. This setup allows hybridize, leading reflections at ends constriction. We find that electronic running one can be reflected back opposite multiple times, giving rise Fabry-P\'erot resonant vortices within with well-defined peaks. show magnetic barriers allow manipulate these peaks and obtain significant system spin-resolved magnetoconductance.