The perovskite oxides are known to be susceptible to structural distortions over a long wavelength when compared to their parent cubic structures. From an ab initio simulation perspective, this requires accurate calculations including many thousands of atoms; a task well beyond the remit of traditional plane wave-based density functional theory (DFT). We suggest that this void can be filled using the methodology implemented in the large-scale DFT code, CONQUEST , using a local pseudoatomic orbital (PAO) basis. Whilst this basis has been tested before for some structural and energetic properties, none have treated the most fundamental quantity to the theory, the charge density n ( r ) itself. An accurate description of n ( r ) is vital to the perovskite oxides due to the crucial role played by short-range restoring forces (characterised by bond covalency) and long range Coulomb forces as suggested by the soft-mode theory of Coc...

中文翻译：

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伪原子轨道基础：ABO 3钙钛矿中的电子精度和软模畸变

与它们的母体立方结构相比，已知钙钛矿氧化物在长波长下易于发生结构变形。从头算仿真的角度来看，这需要精确的计算，包括数千个原子。这项任务远远超出了传统的基于平面波的密度泛函理论（DFT）的职责范围。我们建议可以使用局部伪原子轨道（PAO）在大规模DFT代码CONQUEST中实现的方法来填充此空白。尽管此基础已针对某些结构和高能特性进行了测试，但没有人处理该理论中最基本的量，即电荷密度n（r）本身。