1National Laboratory of Solid State Microstructures, and Department of Physics, Nanjing University, Nanjing 210093 2Department of Physics and Center of Theoretical and Computational Physics, University of Hong Kong, Pokfulam Road, Hong Kong
Abstract：We propose the realization of Majorana fermions (MFs) on the edges of a two-dimensional topological insulator in the proximity with s-wave superconductors and in the presence of transverse exchange field $h$. It is shown that there appear a pair of MFs localized at two junctions and that a reverse in the direction of $h$ can lead to permutation of two MFs. With decreasing $h$, the MF states can either be fused or form one Dirac fermion on the $\pi$-junctions, exhibiting a topological phase transition. This characteristic can be used to detect physical states of MFs when they are transformed into Dirac fermions localized on the $\pi$-junction. A condition of decoupling two MFs is also given.
2017, Vol. 34 
