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arXiv · 0712.3803

Vibronic polarons: comments on a model for the colossal field-resistance effects in manganites

Mladen Georgiev
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Abstract

In addition to mechanisms already proposed to account for the formation in manganites of a small-polaron superlattice above the Curie temperature Tc and to a metallic-like sea of large polarons below Tc, we now consider other observed colossal-resistance inducing fields, such as magnetic, electric, photon, or strain fields. We attribute the charge-ordered phase formation to the occurrence of strong dipolar binding of vibronic small polarons arising from the phonon coupling of highly polarizable two-level orbital systems. These species having associated inherent electric and magnetic off-center dipoles, they couple to the external fields leading to the observed colossal effects. The random phase appears due to polaron band widening in the external field.

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Mladen Georgiev. 2007-12-21. Vibronic polarons: comments on a model for the colossal field-resistance effects in manganites. https://arxiv.org/abs/0712.3803

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