Influence of long-range interactions on charge ordering phenomena on a square lattice

TL;DR

This paper investigates how long-range interactions induce various charge-ordered phases on a square lattice, revealing complex patterns like Wigner crystals and stripe phases through numerical and mean field analyses.

Contribution

It introduces a lattice gas model to study the emergence of charge orderings from long-range interaction frustration, identifying new phases and phase diagrams.

Findings

Identification of Wigner crystal-like phases at low densities

Discovery of stripe phases between densities 1/3 and 1/2

Construction of finite temperature phase diagram using mean field theory

Abstract

Usually complex charge ordering phenomena arise due to competing interactions. We have studied how such ordered patterns emerge from the frustration of a long-ranged interaction on a lattice. Using the lattice gas model on a square lattice with fixed particle density, we have identified several interesting phases; such as a generalization of Wigner crystals at low particle densities and stripe phases at densities in between rho = 1/3 and rho = 1/2. These stripes act as domain walls in the checkerboard phase present at half-filling. The phases are characterised at zero temperatures using numerical simulations, and mean field theory is used to construct a finite temperature phase diagram.