# Charge order and antiferromagnetism in the extended Hubbard model

## TL;DR

This study investigates the phase transitions and boundaries in the extended Hubbard model on a 2D lattice, revealing how interactions influence magnetic and charge order phases and their transition characteristics.

## Contribution

It provides detailed phase boundary analysis and demonstrates the impact of nearest neighbor interactions on phase stability and transition nature in the extended Hubbard model.

## Key findings

- Hysteresis indicates first order phase transitions.
- Nearest neighbor interactions lower the critical temperature for antiferromagnetism.
- Spectral functions and energetics vary across phase transitions.

## Abstract

We study the extended Hubbard model on a two-dimensional half-filled square lattice using the dynamical cluster approximation. We present results on the phase boundaries between the paramagnetic metallic (normal) state and the insulating antiferromagnetic state, as well as between the antiferromagnetic and charge order states. We find hysteresis along the antiferromagnet/charge order and normal/charge order phase boundaries (at larger values of the on-site interaction), indicating first order phase transitions. We show that nearest neighbor interactions lower the critical temperature for the antiferromagnetic phase. We also present results for the effect of nearest neighbor interactions on the antiferromagnetic phase boundary and for the evolution of spectral functions and energetics across the phase transitions.