Interplay of lattice distortion and electronic structure in BaBiO₃

Abstract

We investigate room temperature core level and valence band spectra of BaBiO 3 using x-ray photoemission spectroscopy and band structure calculations. The features in the valence band spectrum were studied using density functional theory (DFT) under local density approximation (LDA) and Tran Blaha modified Becke Johnson (TB mBJ) exchange potential. The calculations were performed for three different structural parameters; monoclinic, cubic and monoclinic (M ). Our results of the core level spectrum and DFT calculations rule out charge disproportionation of the Bi ions. The valence band spectrum displays gap at the Fermi edge and fine structures in the region close to the Fermi edge. The DFT calculation under TB mBJ for the monoclinic structure is able to generate gap and match the energy positions of the fine structure in a better way. Our calculation results show that there are holes in the O 2 p states and unequal transfer of electrons to the states of the Bi ions. Such mechanism could lead to bond disproportionation and its association with the fine structures in the valence band. The current results reveal the significance of strong link between the lattice distortion and electronic structure and hence to its physical properties.

Lattice effects on the physical properties of half-doped perovskite ruthenates

“…In the present compounds, the surface cleaning of the samples was done by scraping until the intensity of feature B is minimum with respect to feature A. We observe that the intensity ratio of feature A to feature B is less as compared to that observed in other transition metal oxides [42][43][44]. This suggests the signals from feature B are intrinsic to the sample.…”

Evidence of lattice strain as a precursor to superconductivity in BaPb0.75Bi0.25O3

“…Such two features have also been observed in the case of Pb 4f 7/2 by Payne et al [43], in the case of PbO 2 sample that is metallic. It is interesting to note that in the case of BaBiO 3 , that is semi conducting, only poorly screened feature is observed [44,45]. The well screened feature arises when the Bi/Pb 4f 7/2 core hole is screened by the transfer of electrons from the ligand and the poorly screened feature arises when no such transfer occurs.…”

Oxide materials as building blocks for artificial topological insulators

“…[138] and in accordance with the theoretically proposed bond disproportionation [115,116,140]. According to Bharath et al [141], a breathing mode is present because of an unequal transfer of electrons from the O 2p state to the different bismuth sites.…”

“…For the A 2 XYO 6 structure, a monoclinic angle of b = 125.72 was used. This is, however, not supported by experimental data: Cox and Sleight [101] and Barath et al [141] found an angle of b = 90.17 and Balandeh et al [138] an angle of b = 90.13 at T = 210 K in single crystals.…”

“…Recently, Bharath et al [141] fabricated BBO single crystals via the solid state method. With diffraction experiments, a monoclinic structure was observed.…”