Magnetic transition and polaron crossover in a two-site single polaron model including double exchange interaction
Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Calcutta 700064, India
Corresponding author: a email@example.com
Published online: 15 December 2000
A two-site double exchange model with a single polaron is studied using a perturbation expansion based on the modified Lang-Firsov transformation. The antiferromagnetic to ferromagnetic transition and the crossover from small to large polaron are investigated for different values of the antiferromagnetic interaction (J) between the core spins and the hopping (t) of the itinerant electron. Effect of the external magnetic field on the small to large polaron crossover and on the polaronic kinetic energy are studied. When the magnetic transition and the small to large polaron crossover coincide for some suitable range of J/t, the magnetic field has very pronounced effect on the dynamics of polarons.
PACS: 71.38.+i – Polarons and electron-phonon interactions / 63.20.Kr – Phonon-electron and phonon-phonon interactions / 75.30.Vn – Colossal magnetoresistance
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000