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PSEUDOSPIN-ELECTRON MODEL IN INFINITE DIMENSIONS

I. V. Stasyuk, A. M. Shvaika

Institute for Condensed Matter Physics,
National Acadamy of Sciences of the Ukraine,

1 Svientsitskii Str., Lviv, UA-290011, Ukraine

Energy spectrum and thermodynamics of the pseudospin--electron
model are investigated in the dynamical mean field approximation
($d=\infty$ limit). In the limit of zero electron correlation
this model is analytically exactly soluble within this
approach: in the $\mu={\rm const}$ regime the first order phase
transition with the jump of the pseudospin mean value
and reconstruction of the electron spectrum can be
realized, while in the $n={\rm const}$ regime the phase separation
in electron subsystem can take place for certain values of the
model parameters. On the basis of the obtained results the
applicability of the approximate schemes previously used for the
investigation of the pseudospin--electron model are discussed.

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