Influence of superconducting leads energy gap on electron transport through double quantum dot by Markovian quantum master equation approach

TL;DR

This paper investigates how superconducting leads' energy gaps influence electron transport in double quantum dots using a Markovian quantum master equation, revealing effects on populations, coherencies, and current flow.

Contribution

It introduces a finite-temperature quantum master equation approach to analyze the impact of superconducting gaps on double quantum dot transport properties.

Findings

Superconducting gaps significantly affect system populations and coherencies.

Energy contributions from various couplings influence current and coherence.

Larger gaps can enhance current by affecting coherency amplitude and lifetime.

Abstract

The superconducting reservoir effect on the current carrying transport of a double quantum dot in Markovian regime is investigated. For this purpose, a quantum master equation (QME) at finite temperature is derived for the many-body density matrix of an open quantum system. The dynamics and the steady-state properties of the double quantum dot system for arbitrary bias are studied. We will show that how the populations and coherencies of the system states are affected by superconducting leads. The energy parameter of system contains essentially four contributions due to dots system-electrodes coupling, intra dot coupling, two quantum dots inter coupling and superconducting gap. The coupling effect of each energy contribution is applied to currents and coherencies results. In addition, the effect of energy gap is studied by considering the amplitude and lifetime of coherencies to get more current through the system.