Orbital polaron lattice formation in lightly doped La1-xSrxMnO3

TL;DR

This paper demonstrates the formation of an orbital polaron lattice in lightly doped La1-xSrxMnO3 using resonant x-ray scattering, revealing its role in the material's magnetic and electronic properties.

Contribution

It provides direct experimental evidence of the orbital polaron lattice formation at the metal-insulator transition in La1-xSrxMnO3.

Findings

Orbital polaron lattice develops at the metal-insulator transition.

The orbital reordering explains coexistence of ferromagnetism and insulation.

Lattice structure quadruples parallel to MnO2-planes.

Abstract

By resonant x-ray scattering at the Mn K-edge on La7/8Sr1/8MnO3, we show that an orbital polaron lattice (OPL) develops at the metal-insulator transition of this compound. This orbital reordering explains consistently the unexpected coexistence of ferromagnetic and insulating properties at low temperatures, the quadrupling of the lattice structure parallel to the MnO2-planes, and the observed polarization and azimuthal dependencies. The OPL is a clear manifestation of strong orbital-hole interactions, which play a crucial role for the colossal magnetoresistance effect and the doped manganites in general.