Revealing the spin-polarized optical properties of monoclinic α-Eu2(MoO4)3: a DFT + U approach

Abstract

The spin polarized complex first-order linear optical dispersion reveals the spin-polarized electronic structure of α-Eu₂(MoO₄)₃. Calculation explored the influence of the generalized gradient approximation plus the Hubbard Hamiltonian (GGA + U) on the band dispersion and the energy band gap of the spin-up and spin-down and hence on the optical transitions. The appearance of Eu-4f states on the conduction band minimum of the spin-up case causes a significant influence on the ground state properties of α-Eu₂(MoO₄)₃. The calculated optical properties reveal that α-Eu₂(MoO₄)₃ possesses an indirect energy gap of about 2.2 eV (↑) and 3.2 eV (↓) in close agreement with the measured one (3.74 eV). The all-electron full potential linear augmented plane wave (FPLAPW + lo) method within GGA + U was used. We have applied U on the 4f orbitals of Eu atoms and 4d orbitals of Mo atoms to correct the ground state. We have taken a careful look at the valence band's electronic charge density distribution to visualize the charge transfer and the chemical bonding characteristics. The optical properties were calculated seeking deep insight into the electronic structure. It has been found that α-Eu₂(MoO₄)₃ exhibits positive uniaxial anisotropy and negative birefringence for spin-up and spin-down configurations.