Difference in the Electronic Structure of SrBi2Ta2O9 and SrBi2Nb2O9

We calculated the electronic structures of SrBi 2 Ta 2 O 9 (SBT) and SrBi 2 Nb 2 O 9 (SBN) using the discrete variational X α method. We conclude that the difference in the remanent polarization between SBT and SBN is due to the difference in the displacement between tantalum ions and niobium ions rather than the difference in the displacement of the other ions and the difference in ionic charges.