Parameter-free density functional for the correlation energy in two dimensions

TL;DR

This paper introduces a parameter-free density functional for the correlation energy in two-dimensional systems, accurately capturing both homogeneous and inhomogeneous electron correlations, enhancing the predictive power of density-functional theory.

Contribution

It generalizes a previous approximation to a parameter-free form that accurately models correlation energy in 2D systems, including inhomogeneous cases.

Findings

Highly accurate for finite 2D systems

Reproduces correlation energy of homogeneous electron gas

Effective for systems with arbitrary electron numbers

Abstract

Accurate treatment of the electronic correlation in inhomogeneous electronic systems, combined with the ability to capture the correlation energy of the homogeneous electron gas, allows to reach high predictive power in the application of density-functional theory. For two-dimensional systems we can achieve this goal by generalizing our previous approximation [Phys. Rev. B 79, 085316 (2009)] to a parameter-free form, which reproduces the correlation energy of the homogeneous gas while preserving the ability to deal with inhomogeneous systems. The resulting functional is shown to be very accurate for finite systems with an arbitrary number of electrons with respect to numerically exact reference data.