A DFT study of the $UCoGe$ magnetic superconductor

Recently Huy \textit{et al.} (PRL 99, 067006) found that $UCoGe$ is a superconductor coexisting with magnetism. Electronic structure calculations were performed on this compound using the WIEN2k package, results show that its magnetism is anisotropic, with the easy magnetic axis in the $c$-direction. The magnetic moment of the U atom is quite small, but there is a large moment in the Co atom which is in disagreement the experimental result of Huy \textit{et al.}. These results contrast with the isostructural magnetic superconductor $URhGe$, in this latter compound the U-atom magnetic moment is relatively large; while for the Rh atom it is small. The main contribution at $E_F$ is due to U-5f and Co-3d, Ge has little contribution. There are many similarities with the $MgB_2$ superconductor, there are many bands at $E_F$ and $UCoGe$ has a distorted $MgB_2$ crystalline structure, but the superconductivity mechanism seems to be of different origin.