First-principles study of electron transport in few-electron open quantum dots by the Hartree-Fock approach

TL;DR

This study uses first-principles Hartree-Fock calculations to analyze electron transport in few-electron quantum dots, revealing effects like screening, energy level pinning, and Coulomb blockade without adjustable parameters.

Contribution

It introduces a parameter-free, self-consistent Hartree-Fock method for modeling electron transport in quantum dots, capturing non-local effects and Coulomb blockade phenomena.

Findings

Non-local Fock potential alters electron screening and energy levels.

Resonant levels are less pinned and correlate with conductance peaks.

Coulomb blockade is predicted and confirmed by master equation comparison.

Abstract

Electron transport properties of few-electron open quantum dots within the spin-restricted Hartree-Fock approximation are studied. The self-consistent numerical calculations were performed for a whole device, including the semi-infinite leads, without employing any phenomenological or adjustable parameters. Inclusion of the non-local Fock potential brings qualitatively new physics in comparison to the Hartree approach: electron screening decreases, resonant energy levels become less pinned to the Fermi energy and clearly correlate with conductance peaks. When coupling between the dot and leads decreases the number of electrons inside the dot becomes quantized and the model predicts the Coulomb blockade of electron transport. This is confirmed by comparison with the master equation approach for an equivalent quantum dot.