Charging Effects in Ultrasmall Quantum Dots in the Presence of Time-Varying Fields

TL;DR

This paper investigates how charging effects influence time-dependent electron transport in ultrasmall quantum dots, revealing new resonant features and potential for electronic pumping in nonlinear regimes.

Contribution

It introduces a non-Markovian Master equation approach for analyzing charging effects in quantum dots under time-varying fields, including nonlinear responses.

Findings

Identification of new resonant features in Coulomb oscillations and staircase

Demonstration of the possibility to realize electronic pumps

Development of a comprehensive theoretical framework for time-dependent transport

Abstract

The influence of charging effects on time-dependent transport in small semiconductor quantum dots with arbitrary level spectra is studied. Starting from an explicit time-dependent tunneling Hamiltonian, a non-Markovian Master equation is derived which is also valid in the nonlinear response regime. The many-body nonequilibrium distribution functions of the dot are calculated and the I-V characteristic of the structure including the displacement currents is obtained. New resonant features show up in the Coulomb oscillations and in the Coulomb staircase, and a new possibility to realize electronic pumps is described.