Electronic structure and magnetism of UCoGe from first principles

First-principles calculations based on density-functional theory were performed on UCoGe, a ferromagnetic superconductor reported recently [N.T. Huy, A. Gasparini, D.E. de Nijs, Y. Huang, J.C.P. Klaasse, T. Gortenmulder, A. de Visser, A. Hamann, T. Gőrlach, H.v. Lőhneysen, Phys. Rev. Lett. 99 (2007) 067006]. The electronic density of states and magnetic properties were studied using the relativistic full-potential APW plus local-orbitals method and the full-potential local-orbitals (FPLO) method, respectively. A stable ferromagnetic ground state was found. The uranium total magnetic moment is quite small (about 0.1μB) as a result of almost complete cancellation between the spin magnetic moment of 1.2μB and the opposite orbital magnetic moment of 1.1μB, resulting from strong spin–orbit coupling at the uranium site. A magnetic moment of 0.4 and 0.2μB was found at the cobalt site using the APW+lo and the FPLO method, respectively.