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要旨:
The anomalous Hall effect is investigated theoretically by employing
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. If
this case were observable in Mn3Ge, a large AHC of about sigma(zx)
approximate to 900 (Omega cm)(-1) 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 sigma(xy) approximate to 100
(Omega cm)(-1). The non-planar configuration allows a quantitative
evaluation of the topological Hall effect that is seen to determine this
value of sxy 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 sigma(yz) approximate to 250 (Omega cm)(-1).
Copyright (C) EPLA, 2014
