Structural, electronic and optical properties of silver delafossite oxides: A first-principles study with hybrid functional

摘要

Ternary delafossite compounds are potential materials for optoelectronic devices. Employing a first-principles method, we calculate the structural, electronic, and optical properties of the silver based compounds AgMO _2 (M=Al, Ga or In), which crystallize in delafossite structure. Our calculations show that these AgMO_2 oxides have indirect band gaps and the gap energies are in the region of 1.6-3.0 eV whereas, the lowest direct band gap energies are estimated in the range of 2.6-4.3 eV. Furthermore, we find that AgMO_2 compounds exhibit a strong anisotropy for the dielectric function and absorption spectra. The absorption onset for these compounds occurs well above the band gap energies. Overall, we show that the hybrid functional improves the lattice parameters and band gap energies and the calculated values are in good agreement with the experimental values.