Structural, magnetic and electronic properties of FeF2 by first-principle calculation

First-principle calculation was used to investigate the magnetic properties, electronic structure and bonding mechanism of FeF2. By calculating the lattice parameters and magnetic moment as a function of effective interaction parameter (U-eff), it is found that the optimum value of U-eff is equal to 4 eV, the magnetic moment is 3.752 mu B and the value of c/a is 0.704, which are in good agreement with the experiment results. Simultaneously, on the basis of GGA+U method, the electronic structure and bonding mechanism of FeF2 were investigated by the analysis of electron localization function, Bader charge and total charge density. The results show that the bonding behavior between Fe and F atoms is a combination of ionic and covalent bond.