Pressure effect on electronic, elastic and optical properties of Eu:CaF 2 crystal: a first-principles study

The obtained lattice constant, band structure, elastic constants and imaginary part of dielectric function of pure CaF 2 agree well with the experimental and other theoretical results. These properties of Eu:CaF 2 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:CaF 2 , narrowing the bandgap. In addition, it is observed that the optical peaks of Eu:CaF 2 shift towards the longer wavelength side, and the peak intensities drop compared with pure CaF 2 . 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.