Investigations of electronic, elastic, and optical properties of (Ag, Cd)-doped LaAlO3: a computational insight

Abstract

In this study, we used density functional theory to examine how the wide band gap optoelectronic properties of pure, silver-, and cadmium-doped LaAlO3 perovskites changed. Structural, electrical, elastic, and mechanical properties were calculated using generalized gradient approximation. Silver and cadmium incorporated at Al site demonstrated a decreasing trend in the band gap. Both impurities showed the reduction in band gap from 2.98 to 0.468 eV and from 2.98 to 2.0238 eV. The density of states was examined for pristine and doped structures to understand behavioral change of LaAlO3. It was observed that p states in upper valance band and d states in lower conduction band were contributing toward the reduction of band gap. Elastic properties were computed. Elastic parameters were used to calculate Born’s stability and it is predicted that the material is stable mechanically for both pristine and doped forms. Mechanical properties were also predicted and brittle nature was found for both pristine and doped materials. Optical responses such as dielectric function, absorption, and refractive index were also predicted. The impurity inclusion in pristine structure not only reduces the bad gap but also alters the optical behavior. Absorption edge shifted toward lower energy shows a clear redshift, whereas refractive index also reduces from 2.4 to 1.9, making the material more transparent. The absorption spectrum as well as electronic band gap makes this material more useful for solar cell application as well as photocatalytic applications.