Investigation of the spin state of Co in LaCoO3 at room temperature

TL;DR

This study combines experimental photoemission spectroscopy and advanced calculations to determine that Co in LaCoO3 predominantly exists in an intermediate spin state at room temperature, with minimal high spin contribution.

Contribution

It provides a detailed analysis of the spin state of Co in LaCoO3 using combined experimental and theoretical approaches, highlighting the role of spin-orbit interaction.

Findings

Co is mainly in an intermediate spin state at room temperature.

High spin state is not significant at room temperature.

Theoretical calculations match experimental spectra well.

Abstract

We investigate the spin state of LaCoO3 using state-of-the-art photoemission spectroscopy and ab initio band structure calculations. The GGA+U calculations provide a good description of the ground state for the experimentally estimated value of electron correlation strength, U. In addition to the correlation effect, spin-orbit interaction is observed to play a significant role in the case of intermediate spin and high spin configurations. The comparison of the calculated Co 3d and O 2p partial density of states with the experimental valence band spectra indicates that at room temperature, Co has dominant intermediate spin state configuration and that the high spin configuration may not be significant at this temperature. The lineshape of the La 5p and O 2s core level spectra could be reproduced well within these ab initio calculations.