Polaron Absorption in a Perovskite Manganite La0.7Ca0.3MnO3

TL;DR

This study investigates the optical properties of La0.7Ca0.3MnO3, revealing polaron-related absorption features that indicate strong electron-lattice interactions and coupling with spin degrees of freedom in its metallic state.

Contribution

It provides direct experimental evidence of large lattice polarons and their strong coupling in La0.7Ca0.3MnO3, advancing understanding of charge dynamics in manganites.

Findings

Identification of coherent and incoherent polaron bands

Evidence of strong electron-lattice coupling

Interaction between polarons and spin degrees of freedom

Abstract

Temperature dependent optical conductivity spectra of a La0.7Ca0.3MnO3 (LCMO) sample were measured. In the metallic regime at very low temperatures, they clearly showed two types of absorption features, i.e., a sharp Drude peak and a broad mid-infrared absorption band, which could be explained as coherent and incoherent bands of a large lattice polaron. This elementary excitation in LCMO was found to be in a strong coupling regime and to have interactions with the spin degree of freedom.