Two-electron photoemission spectroscopy in topological superconductors

We demonstrate that the photoelectron counting rate, P(2), measured in two-electron coincidence spectroscopy experiments, provides insight into the nature of topological superconductivity. In particular, we show that the spin dependence of P(2) allows one to detect superconducting spin-triplet correlations that are induced in a topological superconductor even in the absence of an associated triplet superconducting order parameter. This ability to detect spin-triplet correlations allows one to distinguish between two recently proposed scenarios for the microscopic origin of topological superconductivity in FeSe0.45Te0.55. Finally, we show that P(2) exhibits a characteristic intensity maximum that can be employed to detect topological phase transitions.