Correlated electronic structure of the kagome metal Mn3Sn

Abstract

${\mathrm{Mn}}_{3}\mathrm{Sn}$ is a fascinating kagome metal exhibiting anomalous Hall effect, spin Hall effect, and anomalous Nernst effect. Using density functional theory plus dynamical mean-field theory ($\mathrm{DFT}+\mathrm{DMFT}$), we investigate the electronic structures of ${\mathrm{Mn}}_{3}\mathrm{Sn}$ in the paramagnetic and noncollinear antiferromagnetic (NAFM) states. In the paramagnetic state, ${\mathrm{Mn}}_{3}\mathrm{Sn}$ has intermediate electronic correlation strength and exhibits typical features of kagome metals including flat bands, Dirac points, and saddle points. In the NAFM state, $\mathrm{DFT}+\mathrm{DMFT}$ calculations reproduce well the experimental Mn magnetic moment and angle-resolved photoemission spectroscopy measurements. Electronic correlation shifts the bands around ${E}_{F}$ and moves the Weyl point between $K$ and $M$ points from $\ensuremath{\sim}40\phantom{\rule{0.28em}{0ex}}\mathrm{meV}$ above ${E}_{F}$ in DFT calculations to $\ensuremath{\sim}5\phantom{\rule{0.28em}{0ex}}\mathrm{meV}$ below ${E}_{F}$, which can strongly enhance the anomalous Hall effect and chiral anomaly observed in ${\mathrm{Mn}}_{3}\mathrm{Sn}$. More importantly, we find that the existence of the Weyl point along the $K\text{\ensuremath{-}}M$ path depends strongly on the ordering pattern of the Mn moments in the NAFM state, which implies that the exotic properties arising from the Weyl points in ${\mathrm{Mn}}_{3}\mathrm{Sn}$ can be manipulated by tuning the ordering pattern of the Mn moments in the NAFM state.