Structural, mechanical, electronic and thermal properties of KZnF3 and AgZnF3 Perovskites: FP-(L)APW+lo calculations

•This work presents a theoretical prediction of the properties of KZnF3 and AgZnF3.•AgZnF3 and KZnF3 are stable materials in the cubic Perovskite structure.•The band structures show that KZnF3 and AgZnF3 exhibit an indirect band gap.

This study presents a theoretical prediction of the structural, mechanical, electronic and thermal properties of the zinc-based Perovskites (AgZnF3 and KZnF3) within the framework of Density Functional Theory (DFT) using All-electron self consistent Full Potential Augmented Plane Waves plus local orbital FP-(L)APW + lo method. To make our work comparable and reliable, several functional were used for the exchange-correlation potential. Also, this study intends to provide a basis and an improvement for updating either the values already predicted by other previous work (by using obsolete functional) or to predict them for the first time. GGA-PBE and GGA-PBEsol were used to predict the structural properties of AgZnF3 and KZnF3 Perovskites such as lattice parameter, bulk modulus and its pressure derivative and the cohesive energy. For these properties, the found values are in very good agreement; also those found by GGA-PBEsol are closer to other available previous and experimental results. The electronic properties of these materials are investigated and compared to provide a consolidated prediction by using the modified Becke Johnson potential TB-mBJ with other functional; the values found by this potential are closer to the available proven results and show that these materials exhibit an indirect gap from R to Γ point. The charge densities plot for [110] direction and QTAIM (Quantum Theory of Atoms in Molecules) theory indicate that ionic character is predominate for (K, Ag, Zn)F bonds. Finally, the effect of temperature and pressure on the unit cell volume, the heat capacity CV and entropy were studied using the quasi-harmonic Debye model.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide