Fully relativistic spin-polarized LMTO calculations of the magneto-opticalKerr effect of d and f ferromagnetic materials. III. Uranium chalcogenidesand pnictides

The optical and magneto-optical (MO) spectra of binary uranium compounds U3 X4 (X=P, As, Sb, Bi, Se, and Te) with the Th3P4 crystal structure, and the ternary UCu2P2 compound are investigated from first principles, using the f ully relativistic Dirac LMTO band structure method and density-functional t heory in the local spin-density approximation (LSDA). The electronic struct ure is obtained with the LSDA, as well as with the so-called LSDA+U approac h which contains an explicit Coulomb interaction U for localized orbitals. Within a bandlike description of the 5f electrons, excellent agreement with the measured MO spectra is obtained for U3P4, U3As4, and UCu2P2. The origi n of the Kerr rotation in the compounds is examined.