Multipole State of Heavy Lanthanide Filled Skutterudites

Abstract

We discuss multipole properties of filled skutterudites containing heavy lanthanide Ln from a microscopic viewpoint on the basis of a seven-orbital Anderson model. For Ln = Gd, in contrast to naive expectation, quadrupole moments remain in addition to main dipole ones. For Ln = Ho, we find an exotic state governed by octupole moment. For Ln = Tb and Tm, no significant multipole moments appear at low temperatures, while for Ln = Dy, Er, and Yb, dipole and higher-order multipoles are dominant. We briefly discuss possible relevance of these multipole states with actual materials.