Electronic band structure, elastic, optical and thermodynamic characteristic of cubic YF3: An ab initio study.

• Some Physical properties for yttrium trifluoride in its cubic structure are investigated. • The calculated thermodynamic properties for YF3 compare with the available experimental data. • The electronic properties calculation reveals that this compound is direct band gap insulator. • The elastic, electronic and the effect of pressure for YF3 are investigated for the first time. We have calculated the bond lengths d F 3 → F 5 , 7 , 8 , d F 4 → F 5 , 6 , 8 , d F 2 → F 5 , 7 , 8 , d F 1 → F 6 , 7 , 8 , d F 1 → 8 − Y 1 , 2 , 3 , d F 9 → Y 1 , 2 , 3 , d F 1 → 8 − F 9 and single-crystal elastic stiffness constants, C ij and polycrystalline elastic moduli at different pressures by using GGA-PBE, GGA-PBESOL and LDA approach for cubic YF 3. Yttrium fluoride is found to be elastically stable in the pressure range 0–40 GPa. Shear modulus, linear compressibility and Poisson's ratio have maximum and minimum values along with different crystallographic directions, which explain their predicted anisotropy. The direct Γ-Γ band gap value 5.082 eV indicates towards the insulating character of YF 3. The broad band gap is a sign that this compound should function as an emission center. We predicted the first and second-order pressure coefficients of direct and indirect band gaps using the GGA-PBE, GGA-PBESOL and LDA approaches. The estimated volumetric thermal expansion coefficient, constants volume and constant pressure heat capacities and entropy at zero pressure and 300 K are 1.66 × 105 K−1, 82.56 J m o l − 1 K − 1 and 83.59 mol-1 K−1, respectively. The edge of the optical absorption is located at 48.5 nm which is caused by the V 1 − C 1 transition at the Γ point in the Brillouin zone that corresponds very well to the direct band gap at Γ- Γ. [ABSTRACT FROM AUTHOR]