The anomalous Hall effect is investigated theoretically by means of density functional calculations for the non-collinear antiferromagnetic order of the hexagonal compounds Mn3Ge and Mn3Sn using various planar triangular magnetic configurations as well as unexpected non-planar configurations. The former give rise to anomalous Hall conductivities (AHC) that are found to be extremely anisotropic. For the planar cases the AHC is connected with Weyl-points in the energy-band structure, which are described in detail. If this case were observable in Mn3Ge, a large AHC of about 900 S/cm should be expected. However, in Mn3Ge it is the non-planar configuration that is energetically favored, in which case it gives rise to an AHC of 100 S/cm. The non-planar configuration allows a quantitative evaluation of the topological Hall effect that is seen to determine this value of the conductivity to a large extent. For Mn3Sn it is the planar configurations that are predicted to be observable. In this case the AHC can be as large as 250 S/cm.
@article{arxiv.1410.5985,
title = {Non-collinear Antiferromagnets and the Anomalous Hall Effect},
author = {Juergen Kübler and Claudia Felser},
journal= {arXiv preprint arXiv:1410.5985},
year = {2015}
}