Ab initio calculations of Nb doped SrTiO₃

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• 作者：R.I. Eglitis ; E.A. Kotomin
• 关键词：Ab initio calculations ; Nb doped SrTiO₃ ; Defects ; Atomic and electronic structure
• 刊名：Physica B
• 出版年：2010
• 出版时间：1 August 2010
• 年：2010
• 卷：405
• 期：15
• 页码：3164-3166
• 全文大小：255 K

文摘

We present and discuss the results of the large scale Hartree–Fock calculations of Nb impurities substituting for Ti ions in SrTiO₃ using ab initio computer code CRYSTAL and several supercells containing up to 135 atoms. The local structure optimisation, the electronic charge redistribution, chemical bond covalence and the band-structure changes induced by the defect are analysed. According to the results of our calculations, Nb is a shallow donor; six nearest O ions are slightly displaced outwards from the Nb ion. The calculated bond population between nearest Ti and O ions (64 me) is much larger than that between Nb and O ions (8 me), since Nb impurity is more ionic than the host Ti.