  Gapped bilayer graphene can support the presence of intragap states due to
kink gate potentials applied to the graphene layers. Electrons in these states
display valley-momentum locking, which makes them attractive for topological
valleytronics. Here, we show that kink-antikink local potentials enable
modulated scattering of topological currents. We find that the kink-antikink
coupling leads to anomalous steps in the junction conductance. Further, when
the constriction detaches from the propagating modes, forming a loop, the
conductance reveals the system energy spectrum. Remarkably, these kink-antikink
devices can also work as valley filters with tiny magnetic fields.
