Magnetic Response of Class DIII Topological Superconductors
Due to the charge neutral and localized nature of surface Majorana modes, detection schemes rely on local spectroscopy or interference through the Josephson effect. We study the magnetic response of a two-dimensional Majorana cone localized at the surface in class DIII Topological Superconductors. For a field parallel to the surface we find that an additional diamagnetic current appears beyond a critical threshold field $H^*$, that leads to a jump in the magnetization. In a spherical configuration Majorana modes always show a finite coupling to arbitrary small applied fields, as an effect of curvature. Meissner screening results in an excess diamagnetic zero-field susceptibility $\propto 1/H^*$, that acquires a universal character in finite geometries. The value of $H^*$ is expected to fall in the Meissner phase for highly doped small band gap Dirac insulators with odd-parity superconductivity.