A theoretical model for tellurite-sulfates Na$_2$Cu$_5$(TeO$_3$)(SO$_4$)$_3$(OH)$_4$ and K$_2$Cu$_5$(TeO$_3$)(SO$_4$)$_3$(OH)$_4$

TL;DR

This paper develops a theoretical model for two tellurite-sulfates, confirming previous speculations about their magnetic couplings and revealing Ising-like magnetization plateaux through numerical simulations.

Contribution

It introduces a compatible theoretical model for the new tellurite-sulfates and validates previous hypotheses about their magnetic interactions using advanced numerical techniques.

Findings

Model confirms mixture of ferromagnetic and antiferromagnetic couplings.

Reveals Ising-like magnetization plateaux at rational saturation values.

Supports previous literature on magnetic couplings.

Abstract

A theoretical model for two new tellurite-sulfates, namely Na$_2$Cu$_5$(TeO$_3$)(SO$_4$)$_3$(OH)$_4$ and K$_2$Cu$_5$(TeO$_3$)(SO$_4$)$_3$ (OH)$_4$ is determined to be compatible with ab-initio calculations. The results obtained in this work show that some previous speculations in the literature about the couplings are correct, obtaining a model with a mixture of ferromagnetic and antiferromagnetic couplings. We use a combination of numerical techniques to study the magnetic properties of the model. Our numerical calculations based on the density-matrix renormalization group method reveal that the system presents Ising-like magnetization plateaux at rational values of the saturation magnetization.