First-principles investigation of symmetric and antisymmetric exchange interactions of SrCu$_{2}$(BO$_{3}$)$_{2}$

TL;DR

This paper uses first-principles calculations to analyze the electronic and magnetic interactions in SrCu₂(BO₃)₂, explaining exchange interactions and confirming results with multiple computational methods.

Contribution

It provides a detailed microscopic explanation of symmetric and antisymmetric exchange interactions in SrCu₂(BO₃)₂ using first-principles methods, including the role of oxygen intra-atomic exchange.

Findings

Good agreement with experimental exchange parameters

Oxygen intra-atomic exchange significantly influences intra-dimer exchange

Microscopic analysis validated by Green function and total energy methods

Abstract

We report on a first-principles investigation of the electronic structure and of the magnetic properties of the quasi-two-dimensional Mott insulator SrCu$_{2}$(BO$_{3}$)$_{2}$. Based on the hopping integrals and Coulomb interactions calculated with LDA and LSDA+U, we provide a microscopic explanation of the symmetric Heisenberg and antisymmetric Dzyaloshinskii-Moriya exchange integrals of SrCu$_{2}$(BO$_{3}$)$_{2}$. The intra-atomic exchange interaction of oxygen is shown to strongly contribute to the intra-dimer isotropic exchange. The results are in good agreement with those derived from experimental data, both regarding the orientation of the Dzyaloshinskii-Moriya vectors and the magnitude of all exchange integrals. The microscopic analysis is confirmed by the results of Green function's and total energies difference methods.