Isotropic pressure-induced electronic band structure of BaTiO₃, SrTiO₃ and CaTiO₃ with its impact on structural and optical properties: ab-initio calculation

ABSTRACT

The present theoretical study offers a comprehensive investigation under the application of systematic external static isotropic pressure, phase stability, electronic-band structure and their impact on the optical characteristics of BaTiO₃, SrTiO₃ and CaTiO₃. All the computational works were performed by Cambridge Serial Total Energy Package, using generalised gradient approximation and density functional theory, Perdue-Burke-Ernzerhof, along with the ultra-soft pseudo-potential for the frozen core. According to structural properties, there is no phase transformation and the structure of all compounds remains cubic. The band structure is a perfect tool to observe the nature of a material, such as an insulator, semiconductor or metal. When the pressure is applied, the band gap of BaTiO₃, SrTiO₃ and CaTiO₃ increases and retains their indirect nature. The total/partial/elemental density of states has been estimated for the full description of the band structure. To verify the authenticity of BaTiO₃, SrTiO₃ and CaTiO₃, various optical parameters have been reported such as the real dielectric functions, imaginary dielectric functions, absorption, refractive index, extinction coefficient, energy loss function and reflectivity. All discrepancies in structural parameters, band structure and optical properties occurred due to applied pressure, and BaTiO₃, SrTiO₃, and CaTiO₃ are connected .

KEYWORDS:

• Isotropic pressure
• stimulated band gap
• phase stability
• hybridisation
• optical properties

Acknowledgement

Thanks are due to the Higher Education Commission (HEC) of Pakistan for the financial support to S. S. A. Gillani under 6934/NRPU/HEC grant number.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author’s agreement

All the authors are well agreed with the contents of this manuscript. Not all of the paper nor any part of this manuscript is under consideration in any journal.

Data availability statement

The raw/processed data required to reproduce these findings cannot be shared at this time as the data also form part of an on-going study.

Additional information

Funding

This work was supported by the Higher Education Commission of Pakistan [grant number 6934/NRPU/HEC].