โ Scribed by Katsunori Kubo; Takashi Hotta
No coin nor oath required. For personal study only.
In order to investigate multipole ordering in f-electron systems from a microscopic viewpoint, we study the so-called G 8 models on three kinds of lattices, simple cubic (sc), bcc, and fcc, based on a j-j coupling scheme with f-electron hopping integrals through รฐff sร bonding. From the G 8 model, we derive an effective model for each lattice structure by using the second-order perturbation theory with respect to รฐff sร. By further applying mean-field theory to the effective model, we find a G 3g antiferro-quadrupole transition for the sc lattice, a G 2u antiferro-octupole transition for the bcc lattice, and a longitudinal triple-q G 5u octupole transition for the fcc lattice.
๐ SIMILAR VOLUMES
The reduction of spatial grid effects in plasma simulations has been studied numerically using higher order multipole expansions and the spline method in one dimension. It is found that, while keeping the higher order moments such as quadrupole and octopole moments substantially reduces the grid eff