Composite Polarons in Ferromagnetic Narrow-band Metallic Manganese Oxides

TL;DR

This paper introduces a new composite polaron model to explain colossal magnetoresistance in ferromagnetic manganese oxides, highlighting how electron-phonon-spin interactions influence their properties.

Contribution

It proposes a novel composite polaron mechanism and analyzes its effects on the ground state and finite-temperature behavior in manganites.

Findings

Energy decreases with composite polaron formation at zero temperature

Effective mass and energy spectrum are strongly temperature and magnetic field dependent

Composite polarons significantly impact transport and thermodynamic properties

Abstract

A new mechanism is proposed to explain the colossal magnetoresistance and related phenomena. Moving electrons accompanied by Jahn-Teller phonon and spin-wave clouds may form composite polarons in ferromagnetic narrow-band manganites. The ground-state and finite-temperature properties of such composite polarons are studied in the present paper. By using a variational method, it is shown that the energy of the system at zero temperature decreases with the formation of composite polaron; the energy spectrum and effective mass of the composite polaron at finite temperature is found to be strongly renormalized by the temperature and the magnetic field. It is suggested that the composite polaron contribute significantly to the transport and the thermodynamic properties in ferromagnetic narrow-band metallic manganese oxides.