Title: Sd-model with strong exchange coupling and a metal-insulator 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)

Sd-exchange model (Kondo lattice model) is formulated for strong sd-coupling within the framework of the X-operators technique and the generating functional approach. The X-operators are constructed based on the exact eigen functions of a single-site sd-exchange Hamiltonian. Such representation enables us to develop a perturbation theory near the atomic level. A locator-type representation was derived for the electron Green's function. The electron self-energy includes interaction of electrons and spin fluctuations. An integral equation for the self-energy 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 metal-insulator phase transition. This transition is similar to that in the Hubbard model at half filling.

Key words: Kondo lattice model, strongly correlated electron systems, metal-insulator phase transitions
PACS: 71.10.-w, 71.10.Fd, 71.27.+a