Double Exchange Alone Does Not Explain the Resistivity of $La_{1-x} Sr_x MnO_3$

TL;DR

This paper challenges the adequacy of the double exchange model in explaining the resistivity of La_{1-x}Sr_xMnO_3, highlighting the importance of electron-phonon interactions due to Jahn-Teller effects.

Contribution

It demonstrates that the double exchange model alone cannot account for the resistivity data and emphasizes the role of electron-phonon interactions in the material.

Findings

Double exchange model is incompatible with resistivity data.

Electron-phonon interactions are crucial for understanding resistivity.

Jahn-Teller splitting significantly influences electronic properties.

Abstract

The $La_{1-x} Sr_x MnO_3$ system with $0.2 \lesssim x \lesssim 0.4$ has traditionally been modelled with a ``double exchange'' Hamiltonian, in which it is assumed that the only relevant physics is the tendency of carrier hopping to line up neighboring spins. We present a solution of the double exchange model, show it is incompatible with many aspects of the resistivity data, and propose that a strong electron-phonon interaction arising from a Jahn-Teller splitting of the outer Mn d-level plays a crucial role.