Magnetic and electronic properties of Cu1−xFexO from first principles calculations

Abstract

Magnetic and electronic properties of Cu_1−xFe_xO systems with x = 6.25% and 12.5% have been investigated using first principles calculations. The ground state of CuO is an antiferromagnetic insulator. At x = 6.25%, Cu_1−xFe_xO systems with Fe on 2 and 4 substitution positions are half-metallic due to the strong hybridization among Fe, the nearest O and Cu atoms, which may come from the double exchange coupling between Fe²⁺–O²⁻–Cu²⁺. At x = 12.5%, Cu_1−xFe_xO system with Fe on 9–11 position has a strong spin polarization near the Fermi level and the system energy is lowest when the doped two Fe atoms form ferromagnetic configuration. This indicates the two doped Fe atoms prefer to form ferromagnetic configuration in Fe²⁺–O²⁻–Cu²⁺–O²⁻–Fe²⁺ chains. While in the Fe on 7–11 position, the spin-down Fe–11 3d states have a large spin polarization near the Fermi level when the two doped Fe atoms form antiferromagnetic configuration. It is concluded that the transition metal doping can modify the magnetism and electronic structures of Cu_1−xFe_xO systems.