Calculated electronic properties of the mixed perovskite oxides:: CaCu3T4O12 (T=Ti, Cr, Mn, Ru) within the DFT

Electronic and magnetic properties of the mixed perovskites CaCu3T4O12 (T=Ti, Cr, Mn, Ru) are calculated ab initio starting from the experimental crystal data. Using the self-consistent band-structure augmented spherical wave (ASW) method built within the local spin-density approximation (LSDA) to the density functional theory (DFT), calculations of the density-of-states (DOS) and of the covalent-energy (E-cov translating the chemical bonding) are performed. From the analyses of the results of the chemical bonding and the DOS at the top of the valence band (VB), an interpretation of the experimental physical properties evidenced experimentally particularly the large dielectric constant for the Ti member and valence degeneracy between Cu and Ru is proposed. (C) 2003 Elsevier B.V. All rights reserved.