Ultraslow electron-phonon scattering and polaron formation in magnetite

Abstract

The comprehensive analysis of AC electrical conductivity in magnetite was performed in order to find relations between the formation of polarons, phonons and conduction by a virtual free electron gas. The analysis performed here for the first time shows experimental data for the behavior of electrons for magnetite with the scattering time shifted to the GHz region. According to our study, the DC electrical conductivity can be described by the virtual free electron gas model, and high frequency conductivity can be described by the combination of the Drude model for disordered materials and Jonscher's universal power law. The observed peak at the imaginary part of AC conductivity was related to the scattering time of the electron-phonon coupling. This interaction between electrons and thermally formed phonons results in the formation of large polarons, and these are responsible for high frequency conductivity in magnetite.