Abstract

From the very beginning of its discovery, the phenomenon of superconductivity has been a source of inspiration for numerous breakthrough concepts and applications. One of the most recent and exciting developments in the field relates to the possibility of spontaneously formed or artificially engineered topological superconductors (TSCs). TSCs constitute systems which harbor exotic charge-neutral excitations termed Majorana fermions (MFs) [1–3]. These are closely related to the particles that Ettore Majorana put forward in 1937 [4] as self-conjugate solutions of the Dirac equation, with the neutrino being considered as the most prominent candidate for a Majorana particle. The crucial difference is that Majorana particles are fundamental and indivisible, while Majorana excitations encountered in TSCs define quasiparticles emerging only in the presence of electron-electron interactions.