The Role of Correlations in the Magnetic Moment of MnSi

TL;DR

This paper investigates the discrepancy between experimental and theoretical magnetic moments in MnSi, revealing that including Hubbard-U corrections leads to lower moments with unusual magnetic properties, though pressure behavior remains inconsistent with experiments.

Contribution

It introduces Hubbard-U corrections into density functional theory calculations to better understand MnSi's low magnetic moment and uncovers novel magnetic states.

Findings

Hubbard-U correction yields lower magnetic moments in MnSi.

Lower moment solutions exhibit unusual magnetic order and quadrupole moments.

Pressure dependence of the magnetic moment does not match experimental observations.

Abstract

We explored the anomalously low moment in MnSi found by experiment (~0.4 $\mu_{\text{B}}$/Mn) vs the moment predicted by density functional theory (~1.0 $\mu_{\text{B}}$/Mn). With the addition of a Hubbard-U correction, we found several solutions with lower moments. These lower moment solutions show an unusual magnetic order and a magnetic quadrupole moment. The behavior of the moment under pressure does not follow the experimental trend.