Mechanical, optoelectronic and thermoelectric properties of the transition metal oxide perovskites YScO3 and LaScO3: First principle calculation

Abstract

In this paper, we report a density functional theory (DFT) calculation study based on the full potential linear augmented plane wave (FP-LAPW) to discuss the mechanical stability as well as the optoelectronic and thermoelectric properties of two proposed orthorhombic transition metal oxide perovskites, namely, YScO3 and LaScO3. We found that our proposed perovskites are mechanically stable and elastically anisotropic materials. Also, they present promising thermal barrier coating (TBC) due to their high mechanical parameters. The topology of the band structure is of a wide energy gap insulator character for our compounds. We tested several functionals to recover the observed band gaps; especially the Eg band gap of LaScO3 has been a challenging problem with conventional exchange-correlation (XC) functionals used in the DFT calculations. Thus, the Yukawa-screened hybrid XC YS-PBE0 successfully gives Eg = 5.78 eV which is in good agreement with the experimental value of 5.8 eV. With DF-PT (perturbation theory) taking into account the lattice vibration, we found that our compounds have a high dielectric constant. We also calculated the main optical properties and found that both compounds have a large optical Eg, very small reflectivity, and could absorb light in the UV region and therefore, making them promising host materials for UV applications and ideal for optoelectronic devices.