Interfaces between Weyl semimetals*

We study junctions of two Weyl semimetals and derive an analytical closed-form condition for the existence of localized modes at the interface. In certain cases, stable interface modes are obtained even when the two Weyl semimetals have identical low energy properties and differ only in their Fermi arc connectivities. This provides further support for the notion that a complete characterization of Weyl semimetals requires not only the nodal configuration in the bulk, but also the connectivity of the Fermi arcs on the surface. These interface modes also have experimental signatures in the quantum oscillation of the density of states.