Polaron transport and lattice dynamics in colossal magnetoresistance manganites

TL;DR

This paper models colossal magnetoresistance in manganites by combining spin double exchange and lattice polaron effects, analyzing transport properties and lattice dynamics across temperature regimes.

Contribution

It introduces a combined model of double exchange and electron-phonon interaction to study transport and lattice effects in manganites, providing new insights into their temperature-dependent behavior.

Findings

Temperature-dependent resistance and magnetoresistance evaluated using the Kubo formula.

Crossover from tunneling to hopping regime of small polarons observed.

Phonon frequency hardening and damping reduction with decreasing temperature.

Abstract

Based on the model combining the spin double exchange and the lattice polaron, we have studied the colossal magnetoresistance phenomena observed in perovskite manganites R_{1-x}A_xMnO_3. First, effects of both the double exchange and the electron-phonon interaction on the transport property are investigated. We have evaluated the temperature dependent resistance and the magnetoresistance using the Kubo formula, and examined the crossover from tunneling to hopping regime of small polarons. Second, effects of the double exchange interaction on the lattice degree of freedom are explored. It is found that both the hardening of the phonon frequency and the reduction of the phonon damping take place with decreasing the temperature.