Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multipole ordering in f-electron systems on the basis of a j-j coupling
  scheme   We investigate microscopic aspects of multipole ordering in f-electron
systems with emphasis on the effect of lattice structure. For the purpose,
first we construct f-electron models on three kinds of lattices, simple cubic
(sc), bcc, and fcc, by including f-electron hopping through (ff\sigma) bonding
in a tight-binding approximation on the basis of a j-j coupling scheme. Then,
an effective model is derived in the strong-coupling limit for each lattice
structure with the use of second-order perturbation theory with respect to
(ff\sigma). By applying mean-field theory to such effective models, we find
different types of multipole ordered state depending on the lattice structure.
For the sc lattice, a \Gamma_{3g} antiferro-quadrupole transition occurs at a
finite temperature and as further lowering temperature, we find another
transition to a ferromagnetic state. For the bcc lattice, a \Gamma_{2u}
antiferro-octupole ordering occurs first, and then, a ferromagnetic phase
transition follows it. Finally, for the fcc lattice, we find a single phase
transition to the longitudinal triple-q \Gamma_{5u} octupole ordering.

31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex