Charge-stripe phases versus a weak anisotropy of nearest-neighbor hopping

TL;DR

This paper demonstrates that weak anisotropy in nearest-neighbor hopping in quantum systems with charge-stripe phases influences their orientation and phase diagram similarity, breaking degeneracy and aligning phases with weaker hopping directions.

Contribution

It shows that anisotropy removes degeneracy and aligns charge-stripe phases, also making fermionic phase diagrams resemble those of hardcore bosons.

Findings

Anisotropy eliminates the $rac{ ext{pi}}{2}$-rotation degeneracy.

Charge-stripe phases align with weaker hopping directions.

Fermionic phase diagrams tend to resemble hardcore boson diagrams.

Abstract

Recently, we demonstrated rigorously the stability of charge-stripe phases in quantum-particle systems that are described by extended Falicov-Kimball Hamiltonians, with the quantum hopping particles being either spinless fermions or hardcore bosons. In this paper, by means of the same methods, we show that any anisotropy of nearest-neighbor hopping eliminates the $\pi/2$-rotation degeneracy of the so called dimeric and axial-stripe phases and orients them in the direction of a weaker hopping. Moreover, due to the same anisotropy the obtained phase diagrams of fermions show a tendency to become similar to those of hardcore bosons.