2015/03/31 by Thomas A. Mellan, Furio Cora, Furio Corà +4 · 69 citations
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Coulomb #Electron #High-pressure geophysics and materials #Magnetic and transport properties of perovskites and related materials #Physics #Quantum mechanics #Rare-earth and actinide compounds #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.92.085151
published in Physical Review B 92(8) (American Physical Society) · Figures 7 and 8 revised. Minor revisions throughout the Results Sections. Table IV revised, Table VI new
arxiv created 2015/08/06 · openalex publication_date 2015/08/28 · arxiv updated 2015/09/02 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
In low-temperature antiferromagnetic LaMnO3, strong and localized electronic interactions among Mn 3d electrons prevent a satisfactory description from standard local density and generalized gradient approximations in density functional theory calculations. Here, we show that the strong on-site electronic interactions are described well only by using direct and exchange corrections to the intraorbital Coulomb potential. Only DFT + U calculations with explicit exchange corrections produce a balanced picture of electronic, magnetic, and structural observables in agreement with experiment. To understand the reason, a rewriting of the functional form of the + U corrections is presented that leads to a more physical and transparent understanding of the effect of these correction terms. The approach highlights the importance of Hund's coupling (intraorbital exchange) in providing anisotropy across the occupation and energy eigenvalues of the Mn d states. This intraorbital exchange is the key to fully activating the Jahn-Teller distortion, reproducing the experimental band gap and stabilizing the correct magnetic ground state in LaMnO3. The best parameter values for LaMnO3 within the DFT (PBEsol) + U framework are determined to be U=8 eV and J=1.9 eV.