Multipole ordering in -electron systems

Kubo, Katsunori; Hotta, Takashi

Physica B; Condensed Matter, 378-380, p.1081 - 1082, 2006/05

https://doi.org/10.1016/j.physb.2006.01.428

In order to investigate multipole ordering in -electron systems from a microscopic viewpoint, we study the so-called models on three kinds of lattices, simple cubic (sc), bcc, and fcc, based on a - coupling scheme with -electron hopping integrals through bonding. From the model, we derive an effective model for each lattice structure by using the second-order perturbation theory with respect to . By further applying mean-field theory to the effective model, we find a antiferro-quadrupole transition for the sc lattice, a antiferro-octupole transition for the bcc lattice, and a longitudinal triple- octupole transition for the fcc lattice.