Electron correlations in double exchange model with orbital degeneracy

We study the effects of the Hubbard interaction among conduction electrons on the double exchange model with the orbital degeneracy. Employing a slave -boson approach to treat the correlation for conduction electrons and a coh erent-potential approximation for the Hund coupling, we calculate the densi ty of states and the optical conductivity. The Hund coupling splits the den sity of states into two parts, which are modified by the band narrowing fac tor arising from the Hubbard interaction. Identifying the decrease of the m agnetization for the localized spin with the increase of the temperature, w e discuss the temperature dependence of the optical conductivity. (C) 2000 Elsevier Science B.V. All rights reserved.