Proposed Detection of the Topological Phase in Ring-Shaped Semiconductor-Superconductor Nanowires Using Coulomb Blockade Transport

Abstract: In semiconductor-superconductor hybrid structures a topological phase transition is expected as a function of chemical potential or magnetic field strength. We show that signatures of this transition can be observed in nonlinear Coulomb blockade transport through a ring shaped structure. In particular, for a fixed electron parity of the ring, the flux periodicity of the neutral excitation spectrum changes from the usual h/2e periodicity to a characteristic h/e periodicity when tuning the system from the topologically trivial to the nontrivial phase. We relate the h/e periodicity to the recently predicted 4\pi periodicity of the Josephson current across a junction formed by two topological superconductors.