Emergent Josephson current of N = 1 chiral topological superconductor in quantum anomalous Hall insulator/superconductor heterostructures

摘要

Recently, a quantum anomalous Hall insulator (QAHI)/superconductor heterostructure has been realized and shows half-quantized conductance plateaus in two-terminal conductance measurements [Q. L. He et al., Science 357,294 (2017)]. The half-quantized conductance plateaus are considered as a solid evidence of chiral Majorana edge modes. However, there is a strong debate over the origin of the half-quantized conductance plateaus. In this work, we propose a Josephson junction based on the QAHI/superconductor heterostructure to identify the existence of chiral Majorana edge modes. We find that the critical Josephson current dramatically increases to a peak value when a half-quantized conductance plateau sigma(12) = e(2)/2 h is showing up for the N = 1 chiral topological superconductor phase with a single chiral Majorana mode. Furthermore, we show that the critical Josephson current of the N = 1 chiral topological superconductor exhibits an h/e-period oscillation and is robust to disorder, in contrast to the behaviors of conventional two-dimensional electron gas systems. We also estimate experimentally relevant parameters and believe that the supercurrent can be observed in experiments.