Kohn-Sham density functional theory for quantum wires in arbitrary correlation regimes

TL;DR

This paper develops a new exchange-correlation functional for Kohn-Sham density functional theory that accurately captures strong correlation effects in quantum wires without symmetry breaking, improving modeling of such systems.

Contribution

It introduces an approximation based on the strong-interaction limit of the Hohenberg-Kohn functional, enhancing the ability to model strongly-correlated regimes in quantum wires.

Findings

Successfully captures charge localization in strongly-correlated regimes.

Reproduces key features of the exact Kohn-Sham potential.

Shows improved results over local density approximation.

Abstract

We use the exact strong-interaction limit of the Hohenberg-Kohn energy density functional to construct an approximation for the exchange-correlation term of the Kohn-Sham approach. The resulting exchange-correlation potential is able to capture the features of the strongly-correlated regime without breaking the spin or any other symmetry. In particular, it shows "bumps" (or barriers) that give rise to charge localization at low densities and that are a well-known key feature of the exact Kohn-Sham potential for strongly-correlated systems. Here we illustrate this approach for the study of both weakly and strongly correlated model quantum wires, comparing our results with those obtained with the configuration interaction method and with the usual Kohn-Sham local density approximation.