Fractional chiral superconductors

• Main Authors: Sagi, Eran, Haim, Arbel, Berg, Erez, Oppen, Felix von, Oreg, Yuval
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: ddc:530; IPY
• Online Access: https://refubium.fu-berlin.de/handle/fub188/21714; https://doi.org/10.17169/refubium-25002; https://doi.org/10.1103/PhysRevB.96.235144

Two-dimensional px+ipy topological superconductors host gapless Majorana edge modes, as well as Majorana bound states at the core of h/2e vortices. Here we establish the possibility of realizing the fractional counterpart of this phase: a fractional chiral superconductor. This exotic phase is shown to give rise to a plethora of non-Abelian bulk excitations and a chiral Z2m parafermion theory on the edge of the sample, where m is an odd integer. In addition, we demonstrate that Z2m parafermionic bound states reside at the cores of h/2e vortices. In certain geometries, the system can support a fractional Josephson junction with 4πm periodicity, reflecting the underlying non-Abelian excitations. Finally, we show that the tunneling density of states associated with this edge theory exhibits an anomalous energy dependence of the form ωm−1. Our results are demonstrated through an explicit tractable model, composed of an array of coupled Rashba wires in the presence of strong interactions, Zeeman field, and proximity coupling to an s-wave superconductor.