Understanding the magnetic, electronic and optical properties of Iron titanium Oxyphosphate Fe0.5TiOPO4 using DFT, GGA and GGA+U approaches.

An investigation into the structural, electronic, magnetic and optical properties of oxyphosphate Fe 0.5 TiOPO 4 was conducted using first-principles calculations based on density functional theory (DFT) with the Plane-Wave Self-Consistent Field (PWSCF). The results are used to discuss the quality of the generalized-gradient expansion GGA and GGA+U approximation for describing these atoms. We showed that the obtained symmetry lattice parameter agree well with the experimental results. The influence of iron element on the magnetic and electronic properties of oxyphosphate Fe 0.5 TiOPO 4 is analyzed. The electronic structure calculations for monoclinic oxyphosphate Fe 0.5 TiOPO 4 predict an energy-gap in both spin-up and spin-down. The partial density of states (PDOS) of Fe 0.5 TiOPO 4  show that the oxygen 2p-derived states hybridize strongly with iron-3d at the conduction band when it’s hybridize with titanium and iron at the valance band and the theoretical band gap energy is found to be Eg=0.62eV (GGA) and 2.2 eV (GGA+U).