Role of the superexchange interaction in magnetic transition and polaron crossover
arXiv:cond-mat/0312088 · doi:10.1016/j.physb.2003.11.075
Abstract
The Hubbard-Holstein model is studied including double-exchange interaction and superexchange interaction using a variational phonon basis obtained through the modified Lang-Firsov (MLF) transformation followed by the squeezing transformation. The kinetic energy, polaron crossover and magnetic transition are investigated as a function of electron-phonon (-ph) coupling and electron concentration for different values of antiferromagnetic superexchange interaction () between the core spins. The polaron crossover, magnetic transition and the suppression of ferromagnetic transition with are discussed for the model.
arXiv comment5 pages (RevTeX), accepted in Physica B
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