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Small and large polarons in nickelates, manganites, and cuprates

P. Calvani·P. Dore·S. Lupi·A. Paolone·P. Maselli·P. Giura·B. Ruzicka·S-W. Cheong·W. Sadowski
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Abstract

By comparing the optical conductivities of La_{1.67}Sr_{0.33}NiO_{4} (LSNO), Sr_{1.5}La_{0.5}MnO_4 (SLMO), Nd_2CuO_{4-y} (NCO), and Nd_{1.96}Ce_{0.04}CuO_{4} (NCCO), we have identified a peculiar behavior of polarons in this cuprate family. While in LSNO and SLMO small polarons localize into ordered structures below a transition temperature, in those cuprates the polarons appear to be large, and at low T their binding energy decreases. This reflects into an increase of the polaron radius, which may trigger coherent transport.

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P. Calvani, P. Dore, S. Lupi, A. Paolone, P. Maselli, P. Giura, B. Ruzicka, S-W. Cheong, W. Sadowski. 1997-02-21. Small and large polarons in nickelates, manganites, and cuprates. https://doi.org/10.1007/bf02765706

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