# Thermodynamics of the metal-insulator transition in the extended Hubbard model

## TL;DR

This paper systematically investigates the thermodynamic properties of the extended Hubbard model, highlighting how non-local interactions influence the metal-insulator transition and differ from the standard Hubbard model.

## Contribution

It provides the first comprehensive thermodynamic analysis of the extended Hubbard model, emphasizing the role of non-local interactions in the transition.

## Key findings

- Non-local interactions screen local correlations differently in Fermi-liquid and insulator phases.
- Non-local interactions contribute to first-order metal-insulator transitions in materials.
- Thermodynamics are significantly affected by non-local interactions across the transition.

## Abstract

In contrast to the Hubbard model, the extended Hubbard model, which additionally accounts for non-local interactions, lacks systemic studies of thermodynamic properties especially across the metal-insulator transition. Using a variational principle, we perform such a systematic study and describe how non-local interactions screen local correlations differently in the Fermi-liquid and in the insulator. The thermodynamics reveal that non-local interactions are at least in parts responsible for first-order metal-insulator transitions in real materials.