Theoretical Investigation of Physical Properties of Eu and Er co-doped AlGaN Alloy

Abstract

This study examines the electronic, magnetic, and structural characteristics of wurtzite-structured Al0.25Ga0.75N doped with erbium and europium. Using a variation of the LSDA + U approach, the study takes the important interaction of the 4f shell into account. The results indicate that the co-doped AlGaN displays semiconductor behaviour, and compared to pure Al0.25Ga0.75N, the co-doped material exhibits an indirect band gap with a reduced band gap. The ferromagnetism observed in the co-doped material may be attributed to the mixing of f-p and p-d states, which produces f-p-d hybrid orbitals. The study also reveals the hybridisation of different orbitals in the valence band maximum (VBM), including p-d (Eu-5d, Er-5d, N-2p), and the magnetic moment of the material is strongly localised on the Eu 5.90 µB and Er 2.99 µB site. The real and imaginary components of the dielectric function, refractive index, and extinction coefficient are also calculated and given in the photon energy range up to 12 eV. In the ultraviolet areas of the optical spectrum, the imaginary part of Eu and Er co-doped Al0.25Ga0.75N exhibits a strong absorption coefficient.