Electron density and atomic displacements in KTaO₃

Abstract

The atomic interactions and anharmonicity of atomic displacements in the virtual ferroelectric KTaO3, potassium tantalate, have been studied using accurate single-crystal X-ray diffraction at room temperature. The multipole analysis of electron density and Gram-Charlier series description of anharmonic atomic displacements allowed us to perform a quantitative analysis of the chemical bonding and atomic motion in this crystal. Closed-shell interactions between Ta-O and K-O pairs of atoms were found, while no interaction was observed for the Ta-K and O-O atomic pairs. The character of the anharmonic atomic displacements is discussed and compared with those in SrTiO3.

B-site ordering and strain-induced phase transition in double-perovskite La2NiMnO6 films

“…It is well known that STO and KTO have a cubic perovskite-type structure with a lattice parameter of 0.3905 and 0.3988 nm at room temperature 45,46 , respectively. In contrast, LAO has a rhombohedrally distorted perovskite-type structure 47 , and DSO has an orthorhombically distorted perovskite-type structure at room temperature 48 .…”

Crystal Structure of Molybdenum Tantalum Oxide, Mo2Ta2O11

“…K 2 MoO 4 6) or TaO 6 octahedra (e.g. KTaO 3 7). As mentioned above, exact determination of oxygen positions is rather difficult due to the nearby strongly X‐ray scattering tantalum and molybdenum atoms, resulting in a poor accuracy for the positional parameters of oxygen and, as a result, also for bond lengths and angles.…”

Band Gap Modulation of Tantalum(V) Perovskite Semiconductors by Anion Control

“…A detailed aspect of the electronic structural evolution depending on the anion components was studied by band calculations at the DFT level and the XPS measurements. Structural parameters for DFT calculations were taken from the Rietveld refinements for BaTaO2N, SrTaO2N, and CaTaO2N [10], or from the literature data for KTaO3 [28], NaTaO3 [29], and TaO2F [30]. Since the computation For the d 0 perovskites AMX 3 , it has been well elucidated that the band gap magnitude depends on (i) electronegativity difference between M cation and X anion, (ii) deviation of M−X−M bond angles away from 180 • , (iii) M−X bond distance, and (iv) electronegativity of A cation [25,26].…”