Probing the structural, electronic, mechanical strength and optical properties of tantalum-based oxide perovskites ATaO3 (A = Rb, Fr) for optoelectronic applications: First-principles investigations

Abstract

In the present manuscript, structural, optoelectronic and mechanical properties of perovskite oxides ATaO3 (A = alkali metals = Rb, Fr) have been investigated using first principles study based on density functional theory (DFT). These calculations involve full potential linearly augmented plane wave (FP-LAPW) technique along with Perdew-Burke-Ernzerhof–generalized gradient approximation (PBE-GGA) and PBEsol exchange potentials within the framework of WIEN2K code. In addition, PBE plus Tran and Blaha modified Becke-Johnson (PBE + TB-mBJ) functional have been utilized to improve the electronic properties. These compounds belong to the semiconductor category, which include contributions of Rb-d, Fr-d/f, Ta-d and O-2p orbitals to explore their behavior. Spherical charge density contours illustrate ionic character of Rb and Fr, while significant sharing of the elliptical isolines indicates covalent character between Ta and O. Three independent elastic constants endorse mechanical stability of the studied systems, which also confirm their brittle nature. Because of poor reflectivity, good optical conductivity and absorptivity of incident energetic photons make these materials as potential candidates for wide range of applications, particularly, in optoelectronic like devices.