Electronic structure difference of stoichiometric and off-stoichiometric SBT
Faculty of Tarsus Technical Education, Mersin University, Tarsus, Turkey
2 Dept. of Physics, Faculty of Science and Literature, Kahramanmaras Sutcu Imam Univ., Avsar kampusu, 46100, Kahramanmaras, Turkey
Corresponding author: a email@example.com
Revised: 20 April 2010
Published online: 22 June 2010
X-ray absorption near-edge structure (XANES) calculations of stoichiometric SrBi2Ta2O9 (SBT) and off-stoichiometric Sr0.8Bi2.2Ta2O9 (offstoich-SBT) with space group of A21am have been performed using FEFF 8.2 code, which is based on real space multiple scattering approach. Due to the nature of layered structure of SBT any change in atomic concentration of crystal may cause change in the electronic and magnetic properties. It was observed that lower concentration of Strontium (Sr) lead to an energy shift about 2 eV to higher energies due to the weaker interaction with valency levels of Sr and Oxygen atoms. On the contrary, regarding to offstoich-SBT as a result of higher concentration, Bismuth (Bi) atoms locate closer distances to Oxygen atoms. Hence, Bismuth have energy shifts about 16 eV to lower energy side in M-edge. Such properties lead to change in electronic and ferroelectric properties of SBT.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010