Isospin model for suppression of charge order in hole- doped NaV_2O_5

TL;DR

This paper develops an Ising-like model using an extended pseudospin approach to explain how hole doping suppresses charge order in NaV_2O_5, highlighting the role of Coulomb and hopping energies.

Contribution

It introduces a novel Ising-like model based on pseudospin formalism to qualitatively explain charge order suppression due to hole doping in NaV_2O_5.

Findings

Charge order decreases with increasing hole doping 

The model relates charge order to Coulomb and hopping energy ratios 

Qualitative agreement with experimental doping effects

Abstract

The layered perovskite compound NaV_2O_5 exhibits charge ordering (CO) and spin gap formation which is driven by inter- site Coulomb forces and exchange dimerisation. Experimentally it was found that the CO transition is rapidly reduced by doping. Charge ordering in NaV_2O_5 has a quasi 1D character due to inter- ladder frustration in the Trellis lattice. Based on an extended pseudospin (T=1) approach for hole doped NaV_2O_5 ladders we construct an Ising like model that explains qualitatively the destruction of the CO phase as function of hole doping \delta and show how the CO parameter depends on \delta and the ratio of Coulomb and hopping energies.