Magnetic exchange interactions in the molecular orbital spin system NaV2O5 from a distributed moment point of view
Abstract
The magnetism in NaV2O5 results from doping of the narrow split-off conduction band of V2O5, which becomes half-filled and leads to a Mott-insulating splitting of spin resolved bands with anti-ferromagnetic order of the spins along the zigzag chains. In the Pmmn structure the spin of this S = 1/2 system is equally shared between two vanadium atoms, residing in a molecular orbital type state. While below 34 K a charge disproportionation occurs into V4+ and V5+, the situation above this temperature is less clear and amounts to a fluctuating moment with equal probability of occupancy of each V. While traditionally described as a quarter-filled ladder system with electron spin localized on the rungs of the ladder, we here take a distributed moment approach in terms of the spin density lumped into individual atomic magnetic sites, including the small induced moments on the oxygen atoms. Exchange interactions are calculated between these sites using a linear response approach based on quasiparticle-self-consistent GW band structures. Surprisingly we find the exchange interactions between the small magnetic moments induced on the vanadyl and bridge oxygen sites to be larger than the exchange interactions between vanadium atoms. Their role in the critical temperature is found to be crucial. The spin wave spectra obtained from this classical Heisenberg type Hamiltonian contains unusual optic spin wave type collective excitations of high energy, the significance of which is discussed.
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BibTeX
@misc{turan2026magnetic,
title = {{Magnetic exchange interactions in the molecular orbital spin system NaV2O5 from a distributed moment point of view}},
author = {Ilteris K. Turan and Claudio Garcia and Jerome Jackson and Swagata Acharya and Mark van Schilfgaarde and Walter R L. Lambrecht},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2607.19224},
eprint = {2607.19224},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2607.19224},
}
RIS
TY - UNPB
TI - Magnetic exchange interactions in the molecular orbital spin system NaV2O5 from a distributed moment point of view
AU - Ilteris K. Turan
AU - Claudio Garcia
AU - Jerome Jackson
AU - Swagata Acharya
AU - Mark van Schilfgaarde
AU - Walter R L. Lambrecht
PY - 2026
DA - 2026/10/20
PB - arXiv
DO - 10.48550/arxiv.2607.19224
UR - https://arxiv.org/abs/2607.19224
AB - The magnetism in NaV2O5 results from doping of the narrow split-off conduction band of V2O5, which becomes half-filled and leads to a Mott-insulating splitting of spin resolved bands with anti-ferromagnetic order of the spins along the zigzag chains. In the Pmmn structure the spin of this S = 1/2 system is equally shared between two vanadium atoms, residing in a molecular orbital type state. While below 34 K a charge disproportionation occurs into V4+ and V5+, the situation above this temperature is less clear and amounts to a fluctuating moment with equal probability of occupancy of each V. While traditionally described as a quarter-filled ladder system with electron spin localized on the rungs of the ladder, we here take a distributed moment approach in terms of the spin density lumped into individual atomic magnetic sites, including the small induced moments on the oxygen atoms. Exchange interactions are calculated between these sites using a linear response approach based on quasiparticle-self-consistent GW band structures. Surprisingly we find the exchange interactions between the small magnetic moments induced on the vanadyl and bridge oxygen sites to be larger than the exchange interactions between vanadium atoms. Their role in the critical temperature is found to be crucial. The spin wave spectra obtained from this classical Heisenberg type Hamiltonian contains unusual optic spin wave type collective excitations of high energy, the significance of which is discussed.
ER -