DFT-Based Ab Initio Calculations of Structural, Electronic, Mechanical, and Optical Properties of Ga-based Fluoroperovskite GaXF3 (X = Ca and Sr)

Abstract

This study presents a comprehensive analysis of the structural, mechanical, electronic, and optical properties of GaXF₃ compounds (where X = Ca and Sr), which belong to the perovskite halogenide family with gallium as the base element. The structural stability of GaCaF₃ and GaSrF₃ was confirmed through Birch–Murnaghan equation-of-state optimization using density functional theory (DFT) implemented in CASTEP. Mechanically, these compounds exhibit notable ductility, scratch resistance, anisotropy, mechanical stability, and high resistance to plastic deformation. The electronic band structures reveal insulating behavior, with direct band gaps of 4.1 eV for GaCaF₃ and 4 eV for GaSrF₃ at the M-M symmetry points. To further understand the interactions between different electron states, total density of states (TDOS) and partial density of states (PDOS) analyses were conducted. The wide direct band gaps provide a detailed basis for studying the compounds' optical properties, showing significant optical absorption and conduction in high-energy spectra, while allowing transparency for low-energy photons. These findings suggest that GaCaF₃ and GaSrF₃ are promising materials for advanced electronic devices and energy storage applications, offering a foundation for future research in photocatalysis and optoelectronics.