First Principle Exploration of (K, Rb)(Al, Si)O_{3} Perovskites: Structural, Elastic, Anisotropic, Electronic, and Lattice Dynamical Properties

Abstract

This study explained the structural, elastic, anisotropic, electronic, and lattice dynamical properties of (K, Rb)(Al, Si)O₃, using both the generalized gradient and local density approximations with density functional theory implemented by the Vienna Ab Initio Simulation Package. The calculated elastic constants revealed that current compounds are mechanically stable; over and above, the bulk and shear moduli, Young's modulus, and Poisson's ratio of the compounds investigated were derived from the calculated elastic constants of the compounds considered. Additionally, the electronic behavior of (K, Rb)(Al, Si)O₃ compounds has been explored. The work discovered that the current compounds demonstrated half-metallicity properties relatedly to their electronic properties. The charge transportation of the compounds considered has been assessed utilizing Bader charge analysis. Furthermore, the compounds investigated have demonstrated a dominantly ionic bonding nature. Besides, except for KSiO₃, the calculated magnetic moment was determined to be around 2 µ_B for KAlO₃ and RbAlO₃ and 1 µ_B for RbSiO₃. The vibrational properties of current compounds were discussed and plotted. It was discovered that the RbSiO₃ generalized gradient approximation calculation contains soft modes, although local density approximation has no soft modes. The others are dynamically stable. As far as is known, this study is the first theoretical analysis of (K, Rb)SiO₃ perovskites, and experimental confirmations are still pending. This article can assist in better understanding the compounds considered and motivate further studies.