Condensed Matter Physics, 2006, vol. 9, No. 3(47), p. 545555, English
DOI:10.5488/CMP.9.3.545
Title:
Sdmodel with strong exchange coupling and a metalinsulator
phase transition
Author(s):
 Yu.A.Izyumov
(Institute for Metal
Physics, S.Kovalevskaya str., 18, Ekaterinburg, Russia)
,

 N.I.Chaschin
(Institute for Metal
Physics, S.Kovalevskaya str., 18, Ekaterinburg, Russia)
,

 D.S.Alexeev
(Institute for Metal
Physics, S.Kovalevskaya str., 18, Ekaterinburg, Russia)

Sdexchange model (Kondo lattice model) is formulated for strong
sdcoupling within the framework of the Xoperators technique
and the generating functional approach. The Xoperators are
constructed based on the exact eigen functions of a singlesite
sdexchange Hamiltonian. Such representation enables us to develop
a perturbation theory near the atomic level. A locatortype
representation was derived for the electron Green's function. The
electron selfenergy includes interaction of electrons and spin
fluctuations. An integral equation for the selfenergy was
obtained in the limit of infinite localized spins. A solution of
this equation in the static approximation for spin fluctuations
leads to a structure of electron Green's function showing a
metalinsulator phase transition. This transition is similar to
that in the Hubbard model at half filling.
Key words:
Kondo lattice model, strongly correlated electron
systems, metalinsulator phase transitions
PACS:
71.10.w, 71.10.Fd, 71.27.+a
