Structural and Electronics Properties of Iron (Ii) Oxide Using Density Function Theory

Abstract

The Structural and electronic Properties of Iron(ii)Oxides (F eO) is investigated with density functional theory (DFT) using Quantum Espresso package. Our study is based on Density Functional Theory (DFT) with the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional, Vanderbilt (ultra soft) pseudo potentials and the plane wave basis set implemented in the Quantum-ESPRESSO package. The calcu lation of the total minimum energy and the total minimum force of F eO is 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 sam pling. Moreover, the equilibrium lattice constant is calculated using results obtained from energy convergence test (i.e., 70 Ry and 6 × 6 × 6 ). The computational value of the equilibrium lattice constant is 7.5˚A. This result is underestimated by 8% from the experimental value is 8.19˚A. In addition to this the band structure and total density of state are calculated. From the band structure it is observed that the band gap value is under estimated as compared to the experimental band gap value. This descripancey is due to the inability of GGA to approximate the exchange correlation potential of d and f block elements. The discontinuety of density of state at Fermi level show that FeO is a semiconductor.