Many - body CPA for the Holstein - DE model
نویسنده
چکیده
A many-body coherent potential approximation (CPA) previously developed for the double exchange (DE) model is extended to include coupling to local quantum phonons. The Holstein-DE model studied (equal to the Holstein model for zero Hund coupling) is considered to be a simple model for the colossal magnetoresistance manganites. We concentrate on eeects due to the quantisation of the phonons, such as the formation of polaron subbands. The electronic spectrum and resistivity are investigated for a range of temperature and electron-phonon coupling strengths. Good agreement with experiment is found for the Curie temperature and resistivity with intermediate electron-phonon coupling strength, but phonon quantisation is found not to have a signiicant eeect in this coupling regime.
منابع مشابه
Ferromagnetism and Transport in the Double-Exchange Model, with and without Phonons; Application to the Manganites
An introduction is given to the many-body coherent potential approximation (CPA) for the double-exchange (DE) model and the Holstein-DE model, the latter including coupling of the electrons to local phonons as well as to the local spins. It is shown how the method can treat the local spins and phonons quantum-mechanically and how it is equivalent to dynamical mean field theory in the classical ...
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