Structural, elastic, optoelectronic and optical properties of CuX (X= F, Cl, Br, I): A DFT study

The structural, elastic, electronic and optical properties of copper halides CuX (X= F, Cl, Br, I) are performed by using the full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). The exchange correlation potential was described by generalized gradient approximation (GGA) and Engel-Vosko generalized gradient approximation (EV-GGA). For better electronic properties we have used the modified Becke Johnson (mBJ) potential. Copper Halides, CuX (X= F, CI, Br, I) have zinc-blend structure (B3) and shows direct band gap. The results obtained for band structure using mBJ potential shows a significant improvement over previous theoretical work and gives closer values to the experimental available data. The elastic constants values have also been analyzed for these materials. In the elastic constants it has been found that CuF and CuBr show brittle nature while CuCl and Cul show ductile behaviour. Optical parameters, like the dielectric constant, refractive indices, reflectivity, optical conductivity and absorption coefficient has also been calculated and presented.