On the Stacking Charge Order in NaV2O5

TL;DR

This paper proposes a mechanism explaining the stacking charge order in NaV2O5 by mapping charge degrees of freedom to Ising spins, highlighting the competition between inter-plane couplings and in-plane order.

Contribution

It introduces a novel explanation for stacking charge order in NaV2O5 using a spin model mapping and analysis of inter-plane coupling competition.

Findings

Stacking charge order arises from competition between nearest and next-nearest plane couplings.

The in-plane order is super-antiferroelectric with fourfold degeneracy.

The proposed mechanism aligns with experimental observations of charge stacking in NaV2O5.

Abstract

We propose a mechanism for the observed stacking charge order in the quarter-filled ladder compound NaV2O5. Via a standard mapping of the charge degrees of freedom onto Ising spins we explain the stacking order as a result of competition between couplings of the nearest and next-nearest planes with the 4-fold degenerate super-antiferroelectric in-plane order.