Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie-Paris 6 and CNRS UMR 7588, Campus de Boucicaut, Paris, France.
J Phys Condens Matter. 2010 Aug 4;22(30):305001. doi: 10.1088/0953-8984/22/30/305001. Epub 2010 Jul 2.
We conducted a comparative study of various reconstructions for the (001) surfaces of SrTiO(3), BaTiO(3), SrZrO(3) and BaZrO(3) perovskites through calculations within the density functional theory. The atomic structure, the thermodynamic stability and the charge distribution of ideal AO or BO(2) terminations, as well as the so-called AO or BO(2) double layer reconstructions were analysed, and it was found that of all the BO(2) double layer reconstructions the most stable are the (2 × 2) and the (√2 × √2) ones. This is mainly due to stress release through the formation of long B-chains. On Ti-based perovskites, these double layer reconstructions were found to be thermodynamically stable, which was not the case for Zr-based perovskites, for which AO terminations dominated most of the stability domain. We also found that the BO(2) double layer reconstructions are accompanied by a substantial charge redistribution, with an almost neutral surface plane. This charge redistribution has important consequences for the reactivity and the behaviour of the electric field close to the surface.
我们通过密度泛函理论的计算，对 SrTiO(3)、BaTiO(3)、SrZrO(3) 和 BaZrO(3)钙钛矿的(001)表面的各种重构进行了比较研究。分析了理想 AO 或 BO(2)端的原子结构、热力学稳定性和电荷分布，以及所谓的 AO 或 BO(2)双层重构，结果发现，在所有的 BO(2)双层重构中，最稳定的是(2 × 2)和(√2 × √2)。这主要是由于通过形成长 B 链来释放应力。在基于 Ti 的钙钛矿上，这些双层重构是热力学稳定的，而对于基于 Zr 的钙钛矿则不是，基于 Zr 的钙钛矿的大多数稳定性区域都以 AO 端为主。我们还发现，BO(2)双层重构伴随着大量的电荷重新分布，表面平面几乎呈电中性。这种电荷再分布对表面附近的反应性和电场行为有重要影响。
