MAGNETOPOLARON STATES OF A SPIN-CORRELATED ANTIFERROMAGNET IN THE NEIGHBORHOOD OF THE SPIN-GLASS TRANSITION

The problem of the spectrum of magnetopolaron states of a strongly cor related conducting canted antiferromagnet is solved. The approach used to study the spectrum is based on an atomic representation and a diag ram technique for Hubbard operators. This approach makes it possible t o include strong intra-ion interactions in a first-principles way, and to obtain the dispersion equation for the magnetopolaron spectrum for arbitrary values of the magnitude of the spin, temperature, and magne tic field. In the vicinity of the spin-flip transition an analytic exp ression is obtained for the spectrum of magnetopolaron states that goe s beyond the framework of the quasiclassical approximation. (C) 1998 A merican Institute of Physics.