Weyl points in the ferromagnetic Heusler compound Co 2 MnAl

The anomalous Hall conductivity (AHC) in some ferromagnetic and antiferromagnetic Heusler compounds was theoretically and experimentally found to be exceptionally large. For the case of ferromagnetic Co 2 MnAl we here argue that the large AHC is connected with the appearance of Weyl points near the Fermi energy. We find four Weyl points slightly above the Fermi edge. We describe our analysis for a magnetization being in the (110)-direction. For the possible (100)-direction we find at least four Weyl points, too. We predict that Co 2 MnGa also possesses Weyl points near or at the Fermi energy.