Interference of Majorana fermions in NS junctions

Abstract

We investigate interference of Majorana fermions (MFs) in NS junctions. A general formula of charge conductance G for NS junctions with two MFs is derived based on the low energy effective model. It is found that G for two MFs takes various values 0 \leq G \leq 4e^2/h owing to interference of the MFs, while G is quantized as G = 2e^2/h for a single MF. The value of G is determined by symmetry of the system. As an example, we investigate the complete destructive interference of two degenerate MFs reported by Ii et al. [A. Ii, A. Yamakage, K. Yada, M. Sato, and Y. Tanaka, Phys. Rev. B 86, 174512 (2012)], and identify the symmetry responsible for the destructive interference.