Density functional study of the magnetic properties of $Bi_{4}Mn$ clusters: Discrepancy between theory and experiment

TL;DR

This study uses density functional theory to investigate the magnetic properties of Bi4Mn clusters, revealing multiple isomers with doublet states that may explain experimental observations, highlighting discrepancies with previous theoretical predictions.

Contribution

The paper identifies new isomers with doublet magnetic states in Bi4Mn clusters, providing insights into experimental magnetic measurements not captured by earlier models.

Findings

Identified three local minima with doublet spin states.

Non-collinear calculations do not reduce the magnetic moment.

Proposed that these isomers match experimental results.

Abstract

We have performed collinear and non collinear calculations on neutral Bi4Mn, and collinear ones on ionized Bi4Mn with charges +1 and -1 to find out why theoretical calculations will not predict the magnetic state found in the experiment. We have used the density functional theory to find a fit between the theoretical prediction of the magnetic moment with the experimental value. Our calculations have consisted in a structure search of local energy minima, and then a search of the magnetic lowest energy state for each resulting isomer. The geometry optimization found 3 local minima whose fundamental state is the doublet spin state, which could not be found in previous theoretical works, but they are higher in energy than the lowest-lying isomer by approximately 1.75 eV. This magnetic state could help understand the experiment. Calculations of non-collinear magnetic states for the Bi4Mn do not lower the total magnetic moment. We conclude arguing how the 3 isomers with doublet state could actually be the ones measured in the experiment.