RKKY Interactions of CeB₆ Based on Effective Wannier Model

Abstract

We examine the RKKY interactions of CeB 6 between multipole moments based on the effective Wannier model obtained from the bandstructure calculation including 14 Cef orbitals and 60 conduction orbitals of Ce-d, s and B-p, s. By using the f -c mixing matrix elements of the Wannier model together with the conduction band dispersion, the multipole couplings with the RKKY oscillation are obtained for the active moments in Γ 8 subspace. Both of the Γ 5g quadrupole O xy and the Γ 2u octupole T xyz couplings are largely enhanced with q = (π, π, π) which naturally explains the antiferro-quadrupolar phase of the phase II, and are also enhanced with q = (0, 0, 0) corresponding to the elastic softening of C 44 . Also the couplings of the Γ 5u octupole T β z is quite large for q = (0, 0, π) which is related to the antiferro-octupolar ordering of a possible candidate for the phase IV of Ce x La 1−x B 6 .