6 research outputs found
Lattice Distortion and Octupole Ordering Model in CexLa1-xB6
Possible order parameters of the phase IV in CexLa1-xB6 are discussed with
special attention to the lattice distortion recently observed. A
\Gamma_{5u}-type octupole order with finite wave number is proposed as the
origin of the distortion along the [111] direction. The \Gamma_8 crystalline
electric field (CEF) level splits into three levels by a mean field with the
\Gamma_{5u} symmetry. The ground and highest singlets have the same quadrupole
moment, while the intermediate doublet has an opposite sign. It is shown that
any collinear order of \Gamma_{5u}-type octupole moment accompanies the
\Gamma_{5g}-type ferro-quadrupole order, and the coupling of the quadrupole
moment with the lattice induces the distortion. The cusp in the magnetization
at the phase transition is reproduced, but the internal magnetic field due to
the octupole moment is smaller than the observed one by an order of magnitude.Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jp
Critical Nature of Non-Fermi Liquid in Spin 3/2 Multipolar Kondo Model
A multipolar Kondo model of an impurity spin S_I=3/2 interacting with
conduction electrons with spin s_c=3/2 is investigated using boundary conformal
field theory. A two-channel Kondo (2CK) -like non-Fermi liquid (NFL) under the
particle-hole symmetry is derived explicitly using a ``superspin absorption''
in the sector of a hidden symmetry, SO(5). We discuss the difference between
the usual spin-1/2 2CK NFL fixed point and the present one. In particular, we
find that, unlike the usual 2CK model, the low temperature impurity specific
heat is proportional to temperature.Comment: 4 pages, 2 figure