Helicity-dependent scattering in layered Weyl semimetals

Weyl fermions are characterized by definite helicity, a relation between orientation of the spin and momentum. We investigate controlling helicity utilizing helicity-dependent dynamics due to separation between the Weyl points. We study transport properties of a multilayer structure formed by piece-wise constant scalar and vector potentials and separations between the Weyl points. We show that the transmission spectrum is determined by a relation between the electron momentum and momenta corresponding to Klein tunneling, when the barrier is fully transparent regardless of its width. The helicity dependence of the “Klein momenta” is shown to yield a helicity filtering effect.