Multi-step approach to microscopic models for frustrated quantum magnets - the case of the natural mineral azurite

TL;DR

This paper develops a multi-step theoretical approach combining density functional theory and many-body calculations to accurately model the complex magnetic behavior of the frustrated mineral azurite.

Contribution

It introduces an effective generalized spin-1/2 diamond chain model that unifies various experimental observations of azurite's magnetic properties.

Findings

The model accurately reproduces low-temperature magnetization data.

It explains inelastic neutron scattering and NMR measurements.

The approach successfully describes azurite's specific heat and magnetic susceptibility.

Abstract

The natural mineral azurite Cu$_3$(CO$_3$)$_2$(OH)$_2$ is a frustrated magnet displaying unusual and controversially discussed magnetic behavior. Motivated by the lack of a unified description for this system, we perform a theoretical study based on density functional theory as well as state-of-the-art numerical many-body calculations. We propose an effective generalized spin-1/2 diamond chain model which provides a consistent description of experiments: low-temperature magnetization, inelastic neutron scattering, nuclear magnetic resonance measurements, magnetic susceptibility as well as new specific heat measurements. With this study we demonstrate that the balanced combination of first principles with powerful many-body methods successfully describes the behavior of this frustrated material.