Peierls Instability Induced Ferromagnetic Insulator at Orbital Order Transition

TL;DR

This paper explains the ferromagnetic insulating state in doped manganites as a Peierls instability caused by spin and orbital order interplay, highlighting the role of hole-orbiton-phonon coupling and aligning with recent experimental observations.

Contribution

It introduces a theoretical model linking Peierls instability to ferromagnetic insulation in manganites, emphasizing the significance of hole-orbiton-phonon interactions.

Findings

Peierls instability explains ferromagnetic insulating state

Hole-orbiton-phonon coupling is crucial in doped manganites

Model aligns with experimental reentrant metallic behavior

Abstract

The origin of ferromagnetic insulating state of La$_{7/8}$Sr$_{1/8}$MnO$_3$ is investigated. Based on the tight-binding model, it is shown that this state can be attributed to the Peierls instability arisen from the interplay of spin and orbital ordering. The importance of the hole-orbiton-phonon intercoupling in doped manganites is revealed. This picture explains well the recent experimental finding of the reentrance of ferromagnetic metal state at low temperature [Phys. Rev. Lett. 96, 097201 (2006)].