Improved stability regions for ground states of the extended Hubbard model

TL;DR

This paper investigates the ground state phase diagram of the extended Hubbard model, revealing how local correlations and next-to-nearest neighbor interactions influence phase boundaries and stability regions of key states.

Contribution

It provides improved stability domains for the $ta$-pairing and ferromagnetic states considering realistic interaction parameters.

Findings

Enhanced stability regions for $ta$-pairing state

Expanded ferromagnetic stability at half filling

Interaction parameters align with realistic physical values

Abstract

The ground state phase diagram of the extended Hubbard model containing nearest and next-to-nearest neighbor interactions is investigated in the thermodynamic limit using an exact method. It is found that taking into account local correlations and adding next-to-nearest neighbor interactions both have significant effects on the position of the phase boundaries. Improved stability domains for the $\eta$-pairing state and for the fully saturated ferromagnetic state at half filling have been constructed. The results show that these states are the ground states for model Hamiltonians with realistic values of the interaction parameters.