Hidden Order Parameters and Multipolar Moments in Heavy Fermion Materials

(1)Importance of AF octupole moment in CeB I D 26个D 2 The interaction between two Ce ions was studies microscopically。Assuming that the mixing between the conduction electrons and the f orbital is the dominant mechanism and the(4f)I D10文件D1 state(Ce D 14+文件D 1 is mixed with(4f)I D 11文件D1，we showed that the interaction between O I D 2 xy文件D 2 quadrupoles is the same as the ineraction between T I D 2 xyz文件D 2 octopoles.Thus the importance of T I D2 xyzⅡD2 has been established.(2)Quadrupole order and the nature of AFM state in TmTeTmTe is similar to CeB I D 26锡D2，showing AF quandrupole order.However the crystal structure and the crystal field effects are different。We constructed a microscopic theory of TmTe.An important consequence is that the AFM moments are canted because of the underlying AFQ order.This was confirmed by a experiment.(3)Change ordered state of YB I D 24个D 2 As I D 23个D 2 An Effective Hamiltonian was desived to describe low-temperature properties.

(1) Importance of AF octupole moment in CeBィイD26ィエD2The interaction between two Ce ions was studies microscopically. Assuming that the mixing between the conduction electrons and the f orbital is the dominant mechanism and the (4f)ィイD10ィエD1state (CeィイD14+ィエD1 is mixed with (4f)ィイD11ィエD1, we showed that the interaction between OィイD2xyィエD2 quadrupoles is the same as the ineraction between TィイD2xyzィエD2 octopoles. Thus the importance of TィイD2xyzィエD2 has been established.(2) Quadrupole order and the nature of AFM state in TmTeTmTe is similar to CeBィイD26ィエD2, showing AF quandrupole order. However the crystal structure and the crystal field effects are different. We constructed a microscopic theory of TmTe. An important consequence is that the AFM moments are canted because of the underlying AFQ order. This was confirmed by a experiment.(3) Change ordered state of YBィイD24ィエD2AsィイD23ィエD2An Effective Hamiltonian was desived to describe low-temperature properties.