Effects of Electron Correlation on the Transport through a Quantum Dot Superlattice

TL;DR

This paper investigates how electron correlations influence transport properties in a quantum dot superlattice using a Hubbard model, revealing resonance behaviors and quasi-particle eigenvalues related to conductance peaks.

Contribution

It introduces a method combining Hartree-Fock and second-order self-energy corrections to analyze correlated electron transport in quantum dot superlattices.

Findings

Conductance peaks correspond to resonance states crossing the Fermi energy.

Eigenvalues of the effective Hamiltonian match conductance peak positions.

Correlation effects modify the resonance behavior of electrons.

Abstract

We study correlation effects on the transport through a quantum dot superlattice using a two-dimensional Hubbard model connected to two noninteracting leads. To calculate the zero-temperature conductance away from half-filling, we have used the non-magnetic solution of the Hartree-Fock approximation for the unperturbed Green's function, and then take into account the electron correlation beyond the mean field theory through the second-order self-energy corrections with respect to the residual interaction. When the value of the onsite potential $\epsilon_d$ or the repulsion $U$ is changed, the conductance shows a number of peaks corresponding to the resonance states passing through the Fermi energy. The behavior of the resonance states for correlated electrons can be investigated using the eigenvalue of the effective Hamiltonian for a quasi-particle of a local Fermi liquid. We calculate the eigenvalue using the second-order self-energy, and show explicitly that it can be compared with the conductance peak.