First principles study of structural, electronic and elastic properties of hexagonal copper (I) selenide (Cu₂Se)

Department of Physics, University of Limpopo, Private Bag x1106, Sovenga, 0727, South Africa

^* Corresponding author: moshibudi.ramoshaba@ul.ac.za

Abstract

The first principle calculations within density functional theory, were used to explore the structural, electronic and elastic properties of hexagonal copper (I) selenide (Cu2Se) at room temperature. Lattice constants, minimum energy and equilibrium volume at hexagonal phase were calculated. The lattice parameters of hexagonal Cu2Se were found to be a = b = 8.37 bohr (4.43 Å) and c =9.94 bohr (5.26 Å), corresponding to the minimum energy of -1.15 x 10⁴ eV with the equilibrium volume of 594.93 bohr³. The electronic properties suggest a metallic behaviour with a zero band gap. Calculated elastic constants satisfy all the stability criteria’s of a hexagonal system. The value (118.3 GPa) of Young’s modulus shows that the material is malleable and ductile material. Elastic mechanical behaviour of hexagonal Cu₂Se, suggest stiff, ductile, incompressible, anisotropy and ionic bonding with shear to bulk moduli ratios of 0.38. Furthermore, elastic properties suggest possible consideration of hexagonal Cu2Se for device fabrication in solar cells.