Anti-Klein tunneling in topoelectrical Weyl semimetal circuits

Abstract

Topoelectrical (TE) circuits consisting of capacitors and inductors can be designed to exhibit various Weyl semimetal (WSM) phases in their admittance dispersion. We consider a TE heterojunction circuit consisting of a central region sandwiched by source and drain regions. The energy flux transmission across the heterojunction can be tuned to exhibit perfect transmission near normal incidence (Klein tunneling) for one valley and perfect reflection (anti-Klein tunneling) for the other valley by controlling the WSM phases of the heterojunction. Perfect valley-polarized transmission occurs when the dispersion tilt to Fermi velocity ratio in the source region is reciprocal to that in the central barrier region. This unusual flux transmission is ascribed to two factors, i.e., perfect pseudospin (sublattice) polarization at normal incidence and complete decoupling of one of the sublattice polarizations at the critical velocity ratio. The emergence of anti-Klein tunneling by design in TE circuits suggests a possible realization of the effect in real WSM materials.