Interaction-driven topological superconductivity in one dimension


  Arbel Haim [1]  ,  Konrad Wölms [2]  ,  Erez Berg [1]  ,  Yuval Oreg [1]  ,  Karsten Flensberg [2]  
[1] Department of Condensed Matter Physics, Weizmann Institute of Science
[2] Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen

We study one-dimensional topological superconductivity in the presence of time-reversal symmetry. This phase is characterized by having a bulk gap, while supporting a Kramers' pair of zero-energy Majorana bound states at each of its ends. We present a general simple model which is driven into this topological phase in the presence of repulsive electron-electron interactions. We further propose two experimental setups and show that they realize this model at low energies. The first setup is a narrow two-dimensional topological insulator partially covered by a conventional $s$-wave superconductor, and the second is a semiconductor wire in proximity to an $s$-wave superconductor. These systems can therefore be used to realize and probe the time-reversal invariant topological superconducting phase. The effect of interactions is studied using both a mean-field approach and a renormalization group analysis.