Fermionic phases and their transitions induced by competing finite-range interactions

TL;DR

This paper explores the ground states and phase transitions of one-dimensional fermionic systems with finite-range repulsive interactions, revealing complex charge orderings, phase transition mechanisms, and effects of disorder.

Contribution

It provides a comprehensive classification of charge-ordered states and their transitions for varying interaction ranges, including new insights into abrupt transitions and disorder effects.

Findings

Multiple charge-ordered insulating states with different periodicities.

Phase transitions mediated by liquid, bond-ordered, and re-emergent phases.

Disorder causes phase fragmentization and localization effects.

Abstract

We identify ground states of one-dimensional fermionic systems subject to competing repulsive interactions of finite range, and provide phenomenological and fundamental signatures of these phases and their transitions. Commensurable particle densities admit multiple competing charge-ordered insulating states with various periodicities and internal structure. Our reference point are systems with interaction range $p=2$, where phase transitions between these charge-ordered configurations are known to be mediated by liquid and bond-ordered phases. For increased interaction range $p=4$, we find that the phase transitions can also appear to be abrupt, as well as being mediated by re-emergent ordered phases that cross over into liquid behavior. These considerations are underpinned by a classification of the competing charge-ordered states in the atomic limit for varying interaction range at the principal commensurable particle densities. We also consider the effects of disorder, leading to fragmentization of the ordered phases and localization of the liquid phases.