Decoherence effect on the Fano lineshapes in double quantum dots coupled between normal and superconducting leads

TL;DR

This study examines how decoherence influences Fano lineshapes in a double quantum dot system connected to normal and superconducting leads, revealing suppression of interference patterns and emergence of new structures at low temperatures.

Contribution

It provides new insights into the impact of decoherence on Fano interference in hybrid quantum dot systems, including the formation of Kondo-related features.

Findings

Decoherence suppresses Fano interference patterns.

Proximity effect induces interference at specific energies.

Kondo state formation leads to additional Fano structures.

Abstract

We investigate the Fano-type spectroscopic lineshapes of the T-shape double quantum dot coupled between the conducting and superconducting electrodes and analyze their stability on a decoherence. Because of the proximity effect the quantum interference patterns appear simultaneously at +/- epsilon_2, where epsilon_2 is an energy of the side-attached quantum dot. We find that decoherence gradually suppresses both such interferometric structures. We also show that at low temperatures another tiny Fano-type structure can be induced upon forming the Kondo state on the side-coupled quantum dot due to its coupling to the floating lead.