Ferromagnetism and doublon localization in a Wannier-Hubbard chain

TL;DR

This paper introduces a Wannier-Hubbard model with long-range interactions and hopping, revealing a complex phase diagram with metallic and ferromagnetic phases through DMRG analysis.

Contribution

It derives a new Wannier-Hubbard model with additional interaction terms and explores its phase diagram using numerical methods.

Findings

Identification of metallic and ferromagnetic phases

Discovery of a ferrimagnetic region in the phase diagram

Demonstration of emergent phases under pressure

Abstract

We derive a "Wannier-Hubbard" model consisting of an array of overlapping atomic orbitals interacting via a local Coulomb interaction. Transforming to an orthogonal Wannier basis set, the resulting Hamiltonian displays long range hopping and interactions, with new terms such as correlated hopping and ferromagnetic direct exchange, among others. We numerically study the one-dimensional version of the model at half-filling using the density matrix renormalization group (DMRG) method, unveiling a rich phase diagram as a function of the interaction $U$ and the overlap $s$ with metallic, and ferromagnetic phases, separated by a ferrimagnetic region. Our results indicate a path toward understanding new emergent phases under pressure and beyond standard model Hamiltonians.