Non-stationary effects in the system of coupled quantum dots influenced by the Coulomb correlations

TL;DR

This paper analytically investigates the non-stationary charge dynamics in coupled quantum dots with Coulomb interactions, revealing multiple relaxation times, non-monotonic charge behavior, and a Coulomb-induced period doubling in charge oscillations.

Contribution

It provides an exact analytical solution for the time evolution of electron density in coupled quantum dots considering Coulomb correlations, highlighting new dynamical effects.

Findings

Multiple relaxation rates observed

Non-monotonic charge relaxation behavior

Period doubling in charge oscillations due to Coulomb interaction

Abstract

We found analytical solution for the time evolution of localized electron density in a system of two coupled single-level quantum dots (QDs) connected with continuous spectrum states in the presence of Coulomb interaction. This solution takes into account QD electrons correlation functions of all orders neglecting any correlations between localized and conduction electron filling numbers. We demonstrated that several time scales with the strongly different relaxation rates appear in the system for a wide range of the Coulomb interaction value. We revealed that specific non monotonic behavior of charge relaxation in QD takes place due to Coulomb correlations. We also found out that besides the usual charge oscillations with the period determined by the detuning between the energy levels of the QDs a new effect of period doubling appears in the presence of Coulomb interaction at particular range of the system parameters.