Charge density functional plus $U$ theory of LaMnO$_3$: Phase diagram, electronic structure, and magnetic interaction

TL;DR

This study employs charge density functional plus U calculations to accurately model LaMnO₃, revealing the importance of charge-only density in describing its phase diagram, electronic structure, and magnetic interactions, including clarified magnetic couplings.

Contribution

It introduces the use of spin-unpolarized charge-only density in DFT+U calculations for LaMnO₃, improving the understanding of its phase diagram and magnetic interactions.

Findings

Charge-only density is crucial for correct phase diagram and electronic structure.

Clarification of second neighbor out-of-plane magnetic interaction.

Significant inter-orbital e_g–t_{2g} magnetic coupling due to Jahn-Teller distortion.

Abstract

We perform charge density functional theory plus $U$ calculation of LaMnO$_3$. While all the previous calculations were based on spin density functionals, our result and analysis show that the use of spin-unpolarized charge-only density is crucial to correctly describe the phase diagram, electronic structure and magnetic property. Using magnetic force linear response calculation, a long-standing issue is clarified regarding the second neighbor out-of-plane interaction strength. We also estimate the orbital-resolved magnetic couplings. Remarkably, the inter-orbital $e_g$-$t_{2g}$ interaction is quite significant due to the Jahn-Teller distortion and orbital ordering.