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Direct measurement of polaron binding energy in AMnO$_{3}$ as a function of the A site ionic size by photoinduced IR absorption

T. Mertelj·M. Hrovat·D. Kuščer·D. Mihailovic
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Abstract

Photoinduced IR absorption was measured in undoped (LaMn)_{1-δ}O_{3} and (NdMn)_{1-δ}O_{3}. We observe broadening and a ~44% increase of the midinfrared anti-Jahn-Teller polaron peak energy when La^{3+} is replaced with smaller Nd^{3+}. The absence of any concurent large frequency shifts of the observed PI phonon bleaching peaks and the Brillouin-zone-center internal perovskite phonon modes measured by Raman and infrared spectroscopy indicate that the polaron peak energy shift is mainly a consequence of an increase of the electron phonon coupling constant with decreasing ionic radius on the perovskite A site. This indicates that the dynamical lattice effects strongly contribute to the electronic band narrowing with decreasing in doped giant magnetoresistance manganites.

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T. Mertelj, M. Hrovat, D. Kuščer, D. Mihailovic. 2000-05-04. Direct measurement of polaron binding energy in AMnO$_{3}$ as a function of the A site ionic size by photoinduced IR absorption. https://arxiv.org/abs/cond-mat/0005088

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