Correlation effects in the electronic structure of Mn$_4$ molecular magnet

TL;DR

This study combines theoretical and experimental approaches to analyze the correlation effects in the electronic structure of a Mn4 molecular magnet, revealing it as a strongly correlated Hubbard insulator with an electron gap consistent with optical measurements.

Contribution

The paper demonstrates the importance of many-body effects in Mn4, showing that cluster dynamical mean-field theory accurately predicts its electronic properties unlike simpler methods.

Findings

Mn4 is a Hubbard insulator with strong electron correlations.

Calculated electron gap (1.8 eV) matches optical conductivity data.

Simplified methods fail to reproduce the experimental gap.

Abstract

We present joint theoretical-experimental study of the correlation effects in the electronic structure of (pyH)$_3$[Mn$_4$O$_3$Cl$_7$(OAc)$_3$]$\cdot$2MeCN molecular magnet (Mn$_4$). Describing the many-body effects by cluster dynamical mean-field theory, we find that Mn$_4$ is predominantly Hubbard insulator with strong electron correlations. The calculated electron gap (1.8 eV) agrees well with the results of optical conductivity measurements, while other methods, which neglect many-body effects or treat them in a simplified manner, do not provide such an agreement. Strong electron correlations in Mn$_4$ may have important implications for possible future applications.