Charge density functional plus U theory of LaMnO3: Phase diagram, electronic structure, and magnetic interaction
We perform a charge density functional theory plus U calculation of LaMnO3. While all the previous calculations were based on spin density functionals, our results 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 further addressed regarding the second-neighbor out-of-plane interaction strength. We also estimate the orbital-resolved magnetic couplings. Remarkably, the interorbital eg-t2 g interaction is quite significant due to the Jahn-Teller distortion and orbital ordering.