Volkov-Pankratov states in topological superconductors

This work studies the in-gap states that appear on the boundaries of both one and two dimensional topological superconductors. While these boundaries are guaranteed to host massless Majorana quasiparticles by the bulk-edge correspondence, sufficiently smooth interfaces are shown to give rise to additional massive Volkov-Pankratov states. The authors test these predictions in the case of topological boundaries created by magnetic domain walls present in s-wave superconductors with Rashba spin-orbit coupling.