Vacancy Formation Energy in the Cubic Phase of Magnetite in the Framework of the DFT+U Method

The properties of the cation vacancies in the cubic phase of the magnetic Fe3O4 oxide (magnetite) are calculated using the spin density functional theory with allowance for strong electron correlations (DFT+U method). The influence of the key model parameters (effective Hubbard correction value, supercell size, initial approximations to wavefunctions and electron density) on the description of the electronic structure of the cubic phase of magnetite is analyzed. A procedure is proposed to search for a solution with the lowest total energy, which solves the local minima problem peculiar to DFT+U. The found versions of the charge and orbital orderings of the ground state of the electronic system are characterized. The versions used to optimize the structures of cation vacancy models are described and the corresponding formation energies are determined.