Eglitis Roberts I, Jia Ran
Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., LV1063 Riga, Latvia.
Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
Materials (Basel). 2023 Dec 13;16(24):7623. doi: 10.3390/ma16247623.
We performed B3PW and B3LYP computations for BaTiO (BTO), CaTiO (CTO), PbTiO (PTO), SrTiO (STO), BaZrO (BZO), CaZrO (CZO), PbZrO (PZO) and SrZrO (SZO) perovskite neutral (001) along with polar (011) as well as (111) surfaces. For the neutral AO- as well as BO-terminated (001) surfaces, in most cases, all upper-layer atoms relax inwards, although the second-layer atoms shift outwards. On the (001) BO-terminated surface, the second-layer metal atoms, as a rule, exhibit larger atomic relaxations than the second-layer O atoms. For most ABO perovskites, the (001) surface rumpling is bigger for the AO- than BO-terminated surfaces. In contrast, the surface energies, for both (001) terminations, are practically identical. Conversely, different (011) surface terminations exhibit quite different surface energies for the O-terminated, A-terminated and BO-terminated surfaces. Our computed ABO perovskite (111) surface energies are always significantly larger than the neutral (001) as well as polar (011) surface energies. Our computed ABO perovskite bulk B-O chemical bond covalency increases near their neutral (001) and especially polar (011) surfaces.
我们对钛酸钡（BTO）、钛酸钙（CTO）、钛酸铅（PTO）、钛酸锶（STO）、锆酸钡（BZO）、锆酸钙（CZO）、锆酸铅（PZO）和锆酸锶（SZO）钙钛矿的中性（001）以及极性（011）和（111）表面进行了B3PW和B3LYP计算。对于中性的AO端和BO端（001）表面，在大多数情况下，尽管第二层原子向外移动，但所有上层原子都向内弛豫。在（001）BO端表面，通常第二层金属原子比第二层O原子表现出更大的原子弛豫。对于大多数ABO钙钛矿，AO端（001）表面的起伏比BO端表面更大。相比之下，两种（001）端的表面能实际上是相同的。相反，不同的（011）表面端在O端、A端和BO端表面表现出截然不同的表面能。我们计算得到的ABO钙钛矿（111）表面能总是显著大于中性（001）以及极性（011）表面能。我们计算得到的ABO钙钛矿体相B - O化学键的共价性在其中性（001）尤其是极性（011）表面附近增加。
