Replicas of the Fano resonances induced by phonons in a subgap Andreev tunneling

Abstract

We study influence of the phonon modes on a subgap spectrum and Andreev conductance for the double quantum dot vertically coupled between a metallic and superconducting lead. For the monochromatic phonon reservoir we obtain replicas of the interferometric Fano-type structures appearing simultaneously in the particle and hole channels. We furthermore confront the induced on-dot pairing with the electron correlations and investigate how the phonon modes affect the zero-bias signature of the Kondo effect in Andreev conductance.