Entanglement temperature in molecular magnets composed of S-spin dimers

TL;DR

This study explores quantum thermal entanglement in molecular magnets with spin dimers, introducing an entanglement temperature that correlates with exchange interactions and is specific to antiferromagnetic coupling, validated through experimental comparisons.

Contribution

It introduces the concept of entanglement temperature in molecular magnets and links it to exchange interactions, providing a new way to analyze quantum entanglement in these materials.

Findings

Entanglement temperature $T_e$ is proportional to the exchange interaction $J$.

Entanglement occurs only with antiferromagnetic coupling.

Experimental data from three materials support the theoretical results.

Abstract

In the present work, we investigate the quantum thermal entanglement in molecular magnets composed of dimers of spin $S$, using an Entanglement Witness built from measurements of magnetic susceptibility. An entanglement temperature, $T_{e}$, is then obtained for some values of spin $S$. From this, it is shown that $T_{e}$ is proportional to the intradimer exchange interaction $J$ and that entanglement appears only for antiferromagnetic coupling. The results are compared to experiments carried on three isostructural materials: KNaMSi$_{4}$O$_{10}$ (M$=$Mn, Fe or Cu).