Group theoretical classification of mean-field solutions of degenerate Hubbard model on a triangular lattice

Mean-field solutions of a three-fold degenerate Hubbard model on a two-dime nsional triangular lattice are classified by group theoretical analysis. Fo r ordering vectors corresponding to the points Gamma, K and M in the first BZ 14 types of broken symmetry solutions of non-magnetic state are obtained (6 for Gamma, 6 for K and 2 for M). Furthermore, six types of magnetic sol utions are derived for the Gamma point. Some of the obtained exotic solutio ns are described in detail. (C) 2000 Elsevier Science B.V. All rights reser ved.