Pressure effect on electronic, elastic and optical properties of Eu:CaF₂ crystal: a first-principles study

Abstract

The structure, electronic structure, elastic and optical properties of pure CaF₂ and Eu:CaF₂ are investigated by performing the generalized gradient approximation in the frame of density functional theory. The obtained lattice constant, band structure, elastic constants and imaginary part of dielectric function of pure CaF₂ agree well with the experimental and other theoretical results. These properties of Eu:CaF₂ are also calculated, and it follows that Eu doping leads to the crystal structure distorted, as well as the spin polarization of the system. Especially an impurity band is introduced in the bandgap, above the Fermi level, in the band structure of the Eu:CaF₂, narrowing the bandgap. In addition, it is observed that the optical peaks of Eu:CaF₂ shift towards the longer wavelength side, and the peak intensities drop compared with pure CaF₂. Furthermore, Eu doping induces a series of new peaks in the optical properties, which is probably caused by the transitions of the 4f electrons of the Eu atoms. It is worth mentioning that the effect of pressure on the optical properties of Eu:CaF₂ is also studied, we can hold that the optical peaks will have a blueshift.

Keywords:

• density functional theory
• electronic structure
• elastic property
• optical property
• Eu:CaF₂

Acknowledgments

We also acknowledge the support for the computational resources by the State Key Laboratory of Polymer Materials Engineering of China in Sichuan University.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 11204192].