Electronic structure and magnetic properties of the spin-1/2 Heisenberg system CuSe2O5

TL;DR

This study combines experimental measurements and theoretical calculations to elucidate the electronic structure and magnetic interactions in CuSe2O5, revealing dominant antiferromagnetic couplings and magnetic ordering behavior.

Contribution

It provides a comprehensive microscopic magnetic model for CuSe2O5 based on DFT calculations and experimental data, highlighting the key magnetic couplings and their implications.

Findings

Dominant intra-chain AFM coupling of 165 K

Inter-chain coupling of 20 K

Magnetic ordering temperature of 17 K

Abstract

A microscopic magnetic model for the spin-1/2 Heisenberg chain compound CuSe2O5 is developed based on the results of a joint experimental and theoretical study. Magnetic susceptibility and specific heat data give evidence for quasi-1D magnetism with leading antiferromagnetic (AFM) couplings and an AFM ordering temperature of 17 K. For microscopic insight, full-potential DFT calculations within the local density approximation (LDA) were performed. Using the resulting band structure, a consistent set of transfer integrals for an effective one-band tight-binding model was obtained. Electronic correlations were treated on a mean-field level starting from LDA (LSDA+U method) and on a model level (Hubbard model). In excellent agreement of experiment and theory, we find that only two couplings in CuSe2O5 are relevant: the nearest-neighbour intra-chain interaction of 165 K and a non-frustrated inter-chain coupling of 20 K. From a comparison with structurally related systems (Sr2Cu(PO4)2, Bi2CuO4), general implications for a magnetic ordering in presence of inter-chain frustration are made.