On charge and spin ordering in a one-dimensional model with frustrating interactions

TL;DR

This paper investigates a one-dimensional extended Hubbard model with long-range interactions, revealing multiple charge and spin ordered phases, and draws connections to experimental observations in organic and ladder systems.

Contribution

It identifies new charge and spin ordered ground states in a 1D model with extended interactions and relates these to experimental findings in related materials.

Findings

Two distinct charge-ordered ground states identified.

Spin-ordered states driven by charge order at low energies.

Relevance to experimental observations in organic TMTSF and ladder systems.

Abstract

We study a one-dimensional extended Hubbard model with longer-range Coulomb interactions at quarter-filling in the strong coupling limit. We find two different charge-ordered ground states as the strength of the longer range interactions is varied. At lower energies, these charge ordered states drive two different spin-ordered ground states. A variety of response functions computed here bear a remarkable resemblance to recent experimental observations for organic TMTSF systems, and so we propose that these systems are proximate to a quantum critical point (QCP) associated with T=0 charge order. For a ladder system relevant to Sr_{14}Cu_{24}O_{41}, we find in-chain charge order, rung-dimer, and orbital antiferromagnetic ordered phases with varying interchain couplings and superconductivity with hole-doping.