The Structural, Electronic, Optical and Thermo-Electric Properties of Oxynitride Perovskite CaTaO₂N

Abstract

In this study, we carried out ab-initio calculations of structural, electronic, optical and thermo-electric properties of CaTaO2N compound in Pnma orthorhombic structure, using the full-potential linearized augmented plane wave method (FP-LAPW), within the framework of density functional theory (DFT). The calculated structural parameters are found to be in good agreement with the experimental results. Moreover, we have studied the electronic band structure, total and partial density of states in order to explain the origin of band gaps and the nitrogen anion contribution in the valence and the conduction bands. The CaTaO2N band structure has shown a direct band gap in the direction [Formula: see text] (with the value 2.32[Formula: see text]eV). The optical properties represented by the dielectric functions for CaTaO2N compound have revealed that the Pnma structure absorbs the light at a large window in the edge UV-Vis regions. In order to explain the thermo-electric properties, we have calculated Seebeck coefficient, electrical conductivity, thermal conductivity and the factor figure of merit in this temperature range 100–1000 K. The factor figure of mérit (ZT) of CaTaO2N takes a maximum value of 0.775 at [Formula: see text][Formula: see text]K.

Prediction of a new quaternary Heusler alloy within a good electrical response at high temperature for spintronics applications: DFT calculations

“…The maximum amount of the figure of merit, in which there is semiconductor behavior, is about 0.99 at room temperature. This indicates that the compound fulfills the criterion ZT ≥1 which is generally retained for thermoelectric applications [46]. The investigated compound in the spin down exhibits also a high power factor PF.…”

“…All the required parameters and energy eigenvalues are derived from our previous WIEN2K calculation results. Further details of the thermoelectric calculations can be found in reference [45,46].…”

Recent advances in designing thermoelectric materials

“…2 shows the maximum ZT achieved for bulk thermoelectric materials over the past six years as a function of temperature. 33–234…”

Semi Transparent Three-Dimensional Macroporous Quaternary Oxynitride Photoanodes for Photoelectrochemical Water Oxidation

“…Each material in the simulation was defined by appropriate values for the wavelength-dependent refractive index, n(λ), and optical extinction coefficient, k(λ), from published measurements or simulations of the bulk materials. 38 The simulation was performed for a CaTaO 2 N inverse opal templated by 15 layers of hexagonally close packed (hcp), 300 nm diameter spheres. For comparison, we also simulated a planar photoelectrode with a thickness of 1.2 μm, corresponding to the same volume of CaTa 2 ON.…”