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 Ce-$f$ 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 ${\Gamma }_8$ subspace. Both of the ${\Gamma }_{5g}$ quadrupole $O_{xy}$ and the ${\Gamma }_{2u}$ octupole $T_{xyz}$ couplings are largely enhanced with $\mathbf{q}=(\pi ,\pi ,\pi )$ which naturally explains the antiferro-quadrupolar phase of the phase II, and are also enhanced with $\mathbf{q}=(0,0,0)$ corresponding to the elastic softening of $C_{44}$. Also the couplings of the ${\Gamma }_{5u}$ octupole $T_z^{\beta }$ is quite large for $\mathbf{q}=(0,0,\pi )$ which is related to the antiferro-octupolar ordering of a possible candidate for the phase IV of Ce${}_x$La${}_{1-x}$B${}_6$.

6 pages, 2 figures. arXiv admin note: text overlap with arXiv:1904.06469. Accepted for publication in JPS Conference Proceedings(SCES2019)