Influence of the Degenerate d Level and of the JahnTeller Effect
on the Manganite Electronic Structure Calculated
in the Tight-Binding Approximation

S. M. Dunaevski

St. Petersburg Institute of Nuclear Physics, Russian Academy of Sciences,
Gatchina, St. Petersburg, 188350 Russia

e-mail: dunaevsk@mail.pnpi.spb.ru

Received April 18, 2001

Abstract—E(k) dispersion curves for the charge carriers in the LaMnO₃-like perovskites were calculated for
the basic types of canted antiferromagnetic ordering of the Mn sublattice in the framework of the tight-binding
approximation. The E(k) spectrum of the antiferromagnetic structures was calculated for the first time taking
into account the degeneracy of the Mn e_g level and the Jahn–Teller distortion of the cubic perovskite structure.
This calculation involved diagonalization of the 8 8 Hamiltonian matrix. Analytical expressions for the E(k)
function at separate points and symmetry lines of the Brillouin zone were derived. The calculations showed that
the properties of the La_1–xCa_xMnO₃ system do not have electron–hole symmetry. © 2001 MAIK “Nauka/Inter-
periodica”.

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