Temperature-driven and electrochemical-potential-driven adiabatic pumping via a quantum dot

TL;DR

This paper explores how adiabatic charge pumping in a quantum dot can be driven by periodic changes in reservoir temperatures and electrochemical potentials, highlighting the role of Coulomb interactions and level broadening.

Contribution

It provides analytical formulas for adiabatic charge pumping considering strong dot-reservoir coupling and Coulomb interactions, revealing new mechanisms for temperature-driven pumping.

Findings

Charge pumping is induced by rectification due to delayed response.

Interaction is essential for rectification of charge current.

One-way pumping occurs near the Fermi level regardless of reservoir temperatures.

Abstract

We investigate adiabatic pumping via a single level quantum dot induced by periodic modulation of thermodynamic variables of reservoirs, i.e., temperatures and electrochemical potentials. We consider the impurity Anderson model and derive analytical formulas for coherent adiabatic charge pumping applicable to the strong dot-reservoir coupling within first-order perturbation with respect to Coulomb interaction. We show that charge pumping is induced by rectification effect due to delayed response of the quantum dot to time-dependent reservoir parameters. The presence of interaction is necessary because this delayed response rectifies charge current via Coulomb interaction. For temperature-driven charge pumping, one-way pumping is realized regardless of reservoir temperatures when an energy level of the quantum dot locates near the Fermi level. We clarify that this new feature of adiabatic pumping is caused by level broadening effect of the quantum dot due to strong dot-reservoir coupling.