LAUSR

Ab Initio density functional theory (DFT) simulations have been employed to systematically explore the electronic, optical, elastic, mechanical and vibrational properties. In this study, we revealed that [Formula: see text]-CuI has a wide direct bandgap energy of 3.21 eV, is pure covalent and brittle. We also found that the core level is made up of I s electron orbitals, the valence band is constructed with I p orbitals, and the Cu s orbital states mainly contribute to the conduction band minimum (CBM). The reflectivity of CuI is reported to be low (35.9% for the light reflected), showing high material absorption. A high absorption coefficient of [Formula: see text] cm[Formula: see text] is also reported. The elastic and mechanical properties can further confirm the mechanical stability of the CuI system, derived from DFT-calculated elastic constants and phonon dispersion from density functional perturbation theory (DFPT) calculations.