First-principles calculations of the stability and electronic properties of the PbTiO₃ (110) polar surface

The structural and electronic properties of five terminations of cubic lead titanate (PbTiO₃) (110) polar surface were investigated by first-principles total-energy calculations using a periodic slab model. On the PbTiO termination, an anomalous filling of conduction band was observed, whereas on th...

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Bibliographic Details
Published in:Journal of computational chemistry 2009-09, Vol.30 (12), p.1785-1798
Main Authors: Zhang, Guo-Xu, Xie, Ying, Yu, Hai-Tao, Fu, Hong-Gang
Format: Article
Language:English
Subjects:
first-principles calculation
lead titanate
polar surface
polarity compensation
surface relaxation
thermodynamic stability
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Summary:The structural and electronic properties of five terminations of cubic lead titanate (PbTiO₃) (110) polar surface were investigated by first-principles total-energy calculations using a periodic slab model. On the PbTiO termination, an anomalous filling of conduction band was observed, whereas on the O₂ termination, two surface oxygen atoms formed a peroxo group, demonstrating that the electronic structures of the two stoichiometric terminations undergo significant changes with respect to bulk materials. However, for the three nonstoichiometric TiO-, Pb-, and O-terminated surfaces, their electronic structures are very similar to bulk. Charge redistribution results for the five terminations confirmed that electronic structure and surface composition changes are responsible for their polarity compensation. However, which mechanism actually dominates the stabilization process depends upon energetic considerations. A thermodynamic stability diagram suggested that the two stoichiometric terminations are unstable; however, the three nonstoichiometric terminations can be stabilized in some given regions. Furthermore, this study indicates that the very different stabilities and surface states filling behaviors of the PbTiO₃ (110) polar surface with respect to SrTiO₃ and BaTiO₃ ones seem to originate from the partially covalent characteristics of Pb---O pairs.
ISSN:0192-8651
1096-987X
DOI:10.1002/jcc.21180