Eur. Phys. J. B 76, 203-208 (2010)
https://doi.org/10.1140/epjb/e2010-00186-2

Electronic structure difference of stoichiometric and off-stoichiometric SBT

¹ 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 ozkendir@gmail.com

Received: 4 December 2009
Revised: 20 April 2010
Published online: 22 June 2010

Abstract

X-ray absorption near-edge structure (XANES) calculations of stoichiometric SrBi₂Ta₂O₉ (SBT) and off-stoichiometric Sr_0.8Bi_2.2Ta₂O₉ (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.