Tailoring electronic and optical properties of LaAl[O.sub.3] by Cu inclusion: a DFT study

First principles calculations in the context of density functional theory (DFT) provides a platform to investigate the material's properties in a way to explain the physics of solids. Electronic, structural, and optical properties for pure and Cu-doped LaAl[O.sub.3] are investigated. The study reveals that the band structure of LaAl[O.sub.3] after the inclusion of Cu at the La site is affected significantly. Due to the substitution of Cu, there is a decrease in the band gap from 3.02 eV to 2.95 eV. Furthermore, the partial density of states of LaAl[O.sub.3] changes significantly after Cu doping, which has confirmed the doping effect on intrinsic LaAl[O.sub.3]. The p and d states play a vital role on top of the valence band. The range in which the top of a valence band lies is from 0 eV to -9 eV having a significant effect and it is because of Cu-d states. The optical properties of both pure and doped systems were analyzed. Redshift was observed as absorption edge shifted from 4.5 eV to 4.0 eV and even the refractive index reduces from 2.25 to 1.0, which means the Cu inclusion significantly play its role to tailor optical properties. Hence Cu-doping affects the properties of LaAl[O.sub.3] and makes it a suitable candidate for use in different optical devices. Key words: doping, density functional theory, and gap, density of states, optical properties, refractive index. Des calculs bases sur les principes premiers, dans le cadre de la theorie de la fonctionnelle de densite (TFD/DFT), nous fournissent une plateforme pour examiner les proprietes des materiaux en physique du solide. Nous analysons les proprietes electroniques, structurelles et optiques du LaAl[O.sub.3] pur et dope au Cu. L'etude revele que la structure de bande du LaAl[O.sub.3] est affectee de facon significative apres l'inclusion de Cu sur les sites de La. Suite a cette substitution, la bande interdite (gap) est diminuee de 3.02 eV a 2.95 eV. De plus, la densite partielle d'etats (DPE/PDOS) du LaAl[O.sub.3] change de facon marquee apres le dopage au Cu, ce qui confirme l'effet du dopage sur le LaAl[O.sub.3]. Les etats p et d jouent un role crucial sur le haut de la bande de valence. Le domaine dans lequel se trouve le haut de la bande de valence se situe entre 0 eV et -9 eV, un effet significatif cause par les etats d du Cu. Nous analysons les proprietes optiques des systemes purs et dopes. Un decalage vers le rouge est observe suite au deplacement du seuil d'absorption de 4.5 eV a 4.0 eV et meme l'indice de refraction est reduit de 2.25 a 1.0, ce qui signifie que l'inclusion du Cu joue son role pour ajuster les proprietes optiques. Par consequent, les effets du dopage par le Cu affectent les proprietes du LaAl[O.sub.3] et en font un bon candidat pour utilisation dans les dispositifs optiques. [Traduit par la Redaction] Mots-cles : dopage, theorie de la fonctionnelle de densite, bande interdite, densite d'etats, proprietes optiques, indice de refraction.
1. Introduction The power and energy crises demand that humans establish new ideas and perceptions; therefore different theoretical and experimental methods in research have been developed in the materials field. [...]