Polaron Transport in the Paramagnetic Phase of Electron-Doped Manganites

TL;DR

This study investigates electron transport in lightly doped Ca(1-x)La(x)MnO(3), showing that Feynman polaron theory better explains the data than small-polaron theory, indicating intermediate coupling and specific effective masses.

Contribution

It demonstrates that Feynman polaron theory accurately describes transport in electron-doped manganites, contrasting with hole-doped cases and providing detailed polaron parameters.

Findings

Transport data align with Feynman polaron theory.

Intermediate electron-phonon coupling (alpha ~ 5.4).

Effective and polaron masses estimated at 4.3 m_0 and 10 m_0.

Abstract

The electrical resistivity, Hall coefficient, and thermopower as functions of temperature are reported for lightly electron-doped Ca(1-x)La(x)MnO(3)(0 <= x <= 0.10). Unlike the case of hole-doped ferromagnetic manganites, the magnitude and temperature dependence of the Hall mobility for these compounds is found to be inconsistent with small-polaron theory. The transport data are better described by the Feynman polaron theory and imply intermediate coupling (alpha \~ 5.4) with a band effective mass, m*~4.3 m_0, and a polaron mass, m_p ~ 10 m_0.