DFT-based calculation of Coulomb blockade in molecular junction

TL;DR

This paper introduces a novel method combining DFT with an Ansatz to accurately simulate Coulomb blockade effects in non-equilibrium molecular junctions, improving upon traditional approaches.

Contribution

It presents a new way to incorporate Coulomb blockade corrections into DFT calculations for non-equilibrium molecular transport.

Findings

Successfully modeled Coulomb blockade in a toy molecule

The method agrees with master equation results

Provides a practical approach for non-equilibrium Coulomb effects

Abstract

Quantum transport through single molecules is very sensitive to the strength of the molecule-electrode contact. When a molecular junction weakly coupled to external electrodes, charging effects do play an important role (Coulomb blockade regime). In this regime, the non-equilibrium Green function is usually substituted with master equation approaches, which prevents the density functional theory from describing Coulomb blockade in non-equilibrium case. Last year, we proposed an Ansatz to combine the non-equilibrium Green function technique with the equation of motion method. With help of it, Coulomb blockade was obtained by non-equilibrium Green function, and completely agrees with the master equation results [Phys. Rev. B \textbf{76}, 045408 (2007)]. Here, by the Ansatz, we show a new way to introduce Coulomb blockade correction to DFT calculation in non-equilibrium case. And the characteristics of Coulomb blockade are obtained in the calculation of a $toy$ molecule correctly.