Electronic structure and stability of hexagonalBa3Ti2RuO9

Abstract

We investigated the electronic structure and stability of the hexagonal perovskite Ba 3 Ti 2 RuO 9 using highresolution electron energy loss spectroscopy and first-principles band structure calculations. The comparison between experimental and theoretical results leads to a coherent picture of the electronic structure of this compound where both Ti and Ru ions are tetravalent, the first unoccupied states being of Ru 4d character. Structural relaxations performed on four variants of this compound allowed a detailed investigation of the influence of the Ru atoms location in the hexagonal unit cell and clarified the origin of the stabilization of this phase at room temperature. Two structures without inversion symmetry built, respectively, with two TiRuO 9 units ͑space group P6 3 mc, 186͒ or with one Ru 2 O 9 and one Ti 2 O 9 unit ͑P6m2 , 187͒ are found to be the most stable. The stabilization of the first structure occurs through the polarization of the partially filled Ru 4d bands, whereas a direct metal-metal bonding interaction taking place between the two Ru atoms in the Ru 2 O 9 unit lowers the total energy of the second. The influence of the exchange correlation functional used to perform these calculations on the relative stability of the four variants is discussed.

Evidence of Eu2+ 4f electrons in the valence band spectra of EuTiO3 and EuZrO3

“…In contrast, it is of interest to note that the O-K near edge fine structures of these Eu-containing perovskites are different from the ones in BaTiO 3 , for which Ba 4 f states have been suggested to contribute to clearly distinguishable spectral features 11-13 eV above the edge onset. 29 hybridization between O 2p and Eu 4f states in a 20 eV energy range above the Fermi level. Further information on the Eu 4 f states with respect to the Fermi level cannot be directly inferred from these EELS spectra and we will now present XPS results to this end.…”

Spin-liquid behavior inJeff=12triangular lattice compound Ba3IrTiDey1, Mahajan2, Khuntia3 et al. 2012Phys. Rev. B914860View full textAdd to dashboardCite

“…In the ideal case (i.e., without any site disorder), the Ti (3) [17]. They studied probability of different Ru…”

Interfacial Strain Gradients Control Nanoscale Domain Morphology in Epitaxial BiFeO3 Multiferroic Films

“…The electron energy‐loss near edge structures (ELNES) of the oxygen K‐edge are sensitive to chemical bonding and may give us a hint for electronic structure changes. [ 54,55 ] The oxygen K‐edge evolution along the red line in Figure 4c shows that at the interface a change in peak structure occurs [Figure 4d]. Peaks 1 and 2 (at ≈539 and ≈547 eV respectively) in the BFO film have comparable intensity; however, in the DSO substrate, peak 1 is more intense than peak 2.…”