Deconfinement of Majorana Vortex Modes Produces a Superconducting Landau Level

A spatially oscillating pair potential Δ(r)=Δ0e2iK·r with momentum K>Δ0/ v drives a deconfinement transition of the Majorana bound states in the vortex cores of a Fu-Kane heterostructure (a 3D topological insulator with Fermi velocity v, on a superconducting substrate with gap Δ0, in a perpendicular magnetic field). In the deconfined phase at zero chemical potential the Majorana fermions form a dispersionless Landau level, protected by chiral symmetry against broadening due to vortex scattering. The coherent superposition of electrons and holes in the Majorana Landau level is detectable as a local density of states oscillation with wave vector K2-(Δ0/ v)2. The striped pattern also provides a means to measure the chirality of the Majorana fermions.