Theoretical prediction on the structural, electronic, and polarization properties of tetragonal $Bi2ZnTiO6$ Available to Purchase

We present first-principles investigations on the structural, electronic, and polarization properties of $Bi2ZnTiO6$ using density-functional theory within the generalized gradient approximation. The theoretical structure we obtained confirms the extra large tetragonality observed by experiment. The materials exhibit a semiconductor behavior with an indirect band gap determined by the occupied O $2p$ and unoccupied Bi $6p$ states. There are strong hybridization effects between Bi–O ions, as well as Ti–O and Zn–O ones. The resulting covalent bondings, having a $PbTiO3$-type two-dimensional character, strengthen each other and favor the coupling between the tetragonal distortion of unit cell and the off-center displacement of $A$ and $B$-site cations and O anions due to the existence of Zn, and result in the large tetragonality of this compound. Berry-phase calculation gives the polarization as high as $122μC/cm2$⁠.