Elastic and strain--tunable electronic and optical properties of la2algao6 hybrid perovskite: a first-principles study

Abstract

Perovskite materials, known for their structural versatility and multifunctional properties, continue to draw interest for advanced electronic and optoelectronic applications. In this study, we investigate the elastic and strain--engineered mechanical, electronic properties and optical properties of the orthorhombic La2AlGaO6 (LAGO) hybrid perovskite using first--principles quantum mechanical calculations based on density functional theory (DFT). Structural optimizations were performed using both the local density approximation (LDA) and the generalized gradient approximation (GGA). The mechanical stability of LAGO was confirmed through the Born--Huang criteria, and key elastic constants (C11, C12, C33, C44, and C66) were evaluated. These constants were further used to derive mechanical parameters such as Young's modulus, bulk modulus, shear modulus, Poisson's ratio, Cauchy's pressure, and anisotropic factor, offering insights into the material's ductility, hardness, and elastic anisotropy. Crucially, we explored the influence of biaxial strain on the electronic band structure, DOS/PDOS, and Fermi energy, revealing significant band gap modulation under compressive and tensile strain, and hence, varying the optical properties. The coupling between elastic response and electronic structure highlights LAGO's potential for tunable device applications, where mechanical stimuli can be employed to tailor its electronic functionality.