An ab initio calculation on the structural, electronic and magnetic properties of Ni-doped \(\text{Bi}_{0.5}\text{Na}_{0.5}\text{TiO}_3\)

The first principle calculation was employed to investigate the formation energies and structural, electronic, and magnetic properties of intrinsic and Ni-doped sodium bismuth titanate Bi0.5Na0.5TiO3 (BNT). The obtained formation energies indicate that Ni atoms prefer to dope into Bi-sites in the lattice of BNT while the calculated band structure shows that the doping leads to the emergence of new mid-gap energy states in the bandgaps, reducing the bandgap value of doped materials. The PDOSs reveal that Bi-6p, O-2p and Ti-3d contribute major parts in BNT valence and conduction bands, while the Ni-3d and 4s play the main roles in the formation of new mid-gap states. The spin-resolved density of states, the integrated spin densities and the charge distributions suggest that all doped models exhibit magnetic behavior, mainly due to the interaction of Ni, O and Ti atoms. The study method of this research can be applied to predict new properties of BNT-based materials.