Investigation of structural and electronic Properties of cobalt oxide (coo) using density Functional theory with hubbard correction

Abstract

Cobalt oxide (CoO) has been widely studied due to its many advantages, such as starting material for the manufacture of other chemicals and catalysts, in pigments such as color reagents and in ceramics, a ground-coat frit, promotes the adherence of enamel to steel and also used as a blue coloring agent for pottery, enamel and glass. In this thesis the structural and electronic properties of Cobalt mono-Oxide (CoO) were investigated using density functional theory with Hubbard correction (DFT+U) using Quantum Espresso package. Our study is based on DFT+U with the Perdew- Burke-Ernzerhof (PBE)+U exchange-correlation functional, Vanderbilt (ultra soft) pseudo-potentials and the plane wave basis set implemented in the Quantum-ESPRESSO package. The calculation of the total minimum energy were calculated as a function of cutoff energy and K-points sampling. The total minimum energy per cell is monotonically decreasing with increasing cutoff energy due to variational principle. However, this trend can not be predicted from increasing the k-points sampling. Moreover, the equilibrium lattice constant is calculated using results obtained from energy convergence test (i.e; 40 Ry and 5 × 5 × 5). The computational value of the equilibrium lattice constant is 4.24˚A. This result is in good agreement with experimental value which is 4.27˚A. Finally, discussing band structure (with calculated band-gap=2.45 eV) and density of state of CoO, the electrical property of CoO is determined based on energy band gap.