Stripe phases in the two-dimensional Falicov-Kimball model

TL;DR

This paper investigates the stripe phases in the two-dimensional Falicov-Kimball model, revealing complex behaviors that relate to charge order phenomena observed in high-temperature superconductors and nickelates.

Contribution

It provides the first detailed phase diagram of the 2D Falicov-Kimball model, illustrating mechanisms behind stripe order and phase separation.

Findings

The model exhibits both phase separation and stripe order regimes.

Rich phase behavior depends on model parameters.

Supports theories linking stripe phases to electronic interactions.

Abstract

The observation of charge stripe order in the doped nickelate and cuprate materials has motivated much theoretical effort to understand the underlying mechanism of the stripe phase. Numerical studies of the Hubbard model show two possibilities: (i) stripe order arises from a tendency toward phase separation and its competition with the long-range Coulomb interaction or (ii) stripe order inherently arises as a compromise between itinerancy and magnetic interactions. Here we determine the restricted phase diagrams of the two-dimensional Falicov-Kimball model and see that it displays rich behavior illustrating both possibilities in different regions of the phase diagram.