Quantum perfect crossed Andreev reflection in top-gated quantum anomalous Hall insulator–superconductor junctions
AbstractWe investigate the quantum tunneling and Andreev reflection in a top-gated quantum anomalous Hall insulator proximity coupled with a superconductor junction. A quantized perfect crossed Andreev reflection with its coefficient being integer 1 is obtained and all other scattering processes (the normal reflection, normal tunneling, and local Andreev reflection) are completely suppressed when the topological superconductor phase with Chern number N=1 is realized. This perfect crossed Andreev reflection originates from the tunneling of the chiral Majorana edge states, and the phase of tunneling amplitude only being 0 and π plays a decisive role. Furthermore, because of the chiral characteristic of the Majorana edge states, the perfect crossed Andreev reflection is robust against the disorder and can work in a wide range of system parameters.