DFT study of electronic and structural properties of Sm:GaN

First principle calculations of Sm:GaN carried out using GGA-PBE, mBJ and GGA + U are presented to demonstrate the structural, electronic and magnetic properties of the system. The effects of Hubbard correction (i.e. U) on band structure and location of Sm 4f levels are discussed in detail. The application of U indicated a considerable splitting of occupied and unoccupied 4f band unlike that of GGA and mBJ. The introduction of Sm related gap states caused narrowing of band gap which is expected to facilitate the tuning of optical transitions. The results also indicated the production of intermediate bands in the band gap of host material which points to possible use of this material in photovoltaic cell generation. The observed spin polarization of 4f and 5d and 6s states of Sm shows possibility of ferromagnetic exchange interactions in the material for spintronic devices.