Fractional Spin and Josephson Effect in Time-Reversal-Invariant Topological Superconductors

ARRACHEA, LILIANA; CAMJAYI, ALBERTO; VON OPPEN, FELIX; ALIGIA, ARMANDO

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: Nueva York; Año: 2017 vol. 119

0031-9007

Time-reversal-invariant topological superconducting (TRITOPS) wires are known to host a fractional spin /4 at their ends. We investigate how this fractional spin affects the Josephson current in a TRITOPS-quantum dot-TRITOPS Josephson junction, describing the wire in a model that can be tuned between a topological and a nontopological phase. We compute the equilibrium Josephson current of the full model by continuous-time Monte Carlo simulations and interpret the results within an effective low-energy theory. We show that in the topological phase, the 0-to-π transition is quenched via formation of a spin singlet from the quantum-dot spin and the fractional spins associated with the two adjacent topological superconductors.