Re-examination of half-metallic ferromagnetism for doped LaMnO3 in quasiparticle self-consistent $GW$ method

TL;DR

This study uses the quasiparticle self-consistent $GW$ method to analyze doped LaMnO3, predicting it as a half-metallic ferromagnet and comparing theoretical results with experimental data, revealing discrepancies in spin wave energies.

Contribution

The paper applies the extqsgw\, method to doped LaMnO3, providing new insights into its electronic structure and magnetic excitations, especially regarding the hybridization with phonons.

Findings

Predicts La$_{1-x}$Ba$_x$MnO$_3$ as a fully-polarized half-metallic ferromagnet.

Density of states and dielectric functions align with experimental observations.

Spin wave energies are significantly lower than experimental values, unaffected by structural distortions.

Abstract

We apply the quasiparicle self-consistent $GW$ (\qsgw) method to a cubic virtual-crystal alloy La$_{1-x}$Ba$_x$MnO$_3$ %(LBMO) as a theoretical representative for colossal magnetoresistive perovskite manganites. The \qsgw\ predicts it as a fully-polarized half-metallic ferromagnet for a wide range of $x$ and lattice constant. Calculated density of states and dielectric functions are consistent with experiments. In contrast, the energies of calculated spin wave are very low in comparison with experiments. This is affected neither by rhombohedral deformation nor the intrinsic deficiency in the \qsgw method. Thus we ends up with a conjecture that phonons related to the Jahn-Teller distortion should hybridize with spin waves more strongly than people thought until now.