Title: Electronic Structure of the Perovskite Oxides:<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>La</mml:mi></mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>−</mml:mo><mml:mi mathvariant="italic">x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>Ca</mml:mi></mml:mrow><mml:mrow><mml:mi mathvariant="italic">x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mrow><mml:mi>MnO</mml:mi></mml:…
Abstract: The electronic structures of the perovskite oxides, ${\mathrm{LaMnO}}_{3}$ and ${\mathrm{CaMnO}}_{3}$, are studied using density-functional methods. Antiferromagnetic insulating (AFI) solutions are obtained for both compounds within the local-density approximation (LDA). For ${\mathrm{LaMnO}}_{3}$ the Jahn-Teller distortion, found necessary for the AFI solution, produces occupied $\mathrm{Mn}({z}^{2}\ensuremath{-}1)$ orbitals pointed along the long, basal-plane Mn-O bonds. The large on-site Coulomb $U$ and exchange $J$, obtained from ``constrained'' LDA calculations, $U\ensuremath{\approx}8--10\mathrm{eV}$ and $J\ensuremath{\approx}0.9\mathrm{eV}$, indicate important correlation effects and yield large redistribution of the spectral weight within the $\mathrm{LDA}+U$ approach.