Ab initio electronic structure, magnetism, and magnetocrystalline anisotropy of UGa2

Ab initio electronic structure calculations for the intermetallic compound UGa2 were performed using an optimized linear combination of atomic orbitals method based on the local spin density approximation. Three separate calculations were done treating the uranium 5f states as band states and as localized states with occupation two and three, respectively. In the itinerant approach, spin and orbital moments, magnetocrystalline anisotropy, and the Sommerfeld constant were calculated and found to deviate significantly from the related experimental data. In the localized approach, crystal field parameters were obtained for the 5f states, which have been treated by self-interaction corrected local-density theory. This approach with 5f(2) occupation is shown to provide reasonable results for the anisotropy of the susceptibility, for the field dependence of the magnetic moments, and for the Sommerfeld constant.