We study the in-gap states that appear at the boundaries of both one- A nd two-dimensional topological superconductors. While the massless Majorana quasiparticles are guaranteed to arise by the bulk-edge correspondence we find that they could be accompanied by massive Volkov-Pankratov (VP) states which are present only when the interface is sufficiently smooth. These predictions can be tested in an s-wave superconductor with Rashba spin-orbit coupling placed on top of a magnetic domain wall. We calculate the spin-resolved local density of states of the VP states about the band inversion generated by a magnetic domain wall and find that they are oppositely spin polarized on either side of the topological phase boundary. We also demonstrate that the spatial position energy-level spacing and spin polarization of the VP states can be modified by the introduction of in-plane electric fields.
Publication Source (Journal or Book title)
Physical Review Research
Alspaugh, D., Sheehy, D., Goerbig, M., & Simon, P. (2020). Volkov-Pankratov states in topological superconductors. Physical Review Research, 2 (2) https://doi.org/10.1103/PhysRevResearch.2.023146