Antiferro-quadrupole state of orbital-degenerate Kondo lattice model with configuration

Onishi, Hiroaki  ; Hotta, Takashi*

To clarify a key role of orbitals in the emergence of antiferro-quadrupole structure of PrPb, we investigate the ground-state property of an orbital-degenerate Kondo lattice model by numerical diagonalization techniques. By analyzing an orbital correlation function, it is found that an antiferro-orbital state is favored by the so-called double-exchange mechanism which is characteristic of multi-orbital systems. We will report detailed results of correlation functions and discuss its possible relevance to antiferro-quadrupole structure in PrPb.