First-principles DFT study new series of ruthenates double perovskites Ba2MRuO6 with M = Sc, Ti, V, Cr, Mn, Fe and Co

Abstract

First-principles density functional theory (DFT) within generalized gradient approximation (GGA) and GGA incorporated with Coulomb correlation interaction U (GGA + U) are used to investigate the crystal, electronic, magnetic and optical properties of a new series containing barium-ruthenates double perovskites Ba2MRuO6, with M is being 3d transition-metal ion (M = Sc, Ti, V, Cr, Mn, Fe and Co). All these compounds crystallize in a cubic structure at room-temperature fitting in space-group Fm-3m, with a = b = c ≈ 2a0 (a0 = 4 Å). Ba2MRuO6 oxides show a long-range antiferromagnetic superexchange interaction between neighboring 3d and 4d ions achieved via M3+ (3dn)↑– O2−(2p6)–Ru5+ (4d3)↓. Metallic state exists in Ba2MRuO6 within GGA for M = Sc, Ti, V, Mn, Fe and Co, and semimetallic exists in M = Cr case. While, GGA + U produces half-metallic (HM) state in M = Ti, V, Mn and Co, and insulating state in M = Sc, Cr and Fe cases. In the rest of the paper, total and partial density of states, magnetic moments, bond-valence sums, charge transfer in double perovskites Ba2MRuO6 are computed and discussed in detail. In addition, the real and imaginary parts of the optical dielectric function and energy-loss spectra are computed and the main features shown by their spectra are ascertained on the base of the investigation of density of states.