论文标题
通过偏向势能表面来靶向结构预测的高对称性
Targeting high symmetry in structure predictions by biasing the potential energy surface
论文作者
论文摘要
在自然界中发现的基态结构在许多具有高对称性的情况下。但是结构预测方法通常仅渲染一小部分高对称结构。特别是对于大型晶体细胞，有许多低能缺陷结构。因此，已经开发了方法，其中将优先高的对称结构用作输入，或者在某个对称组中进行整个结构搜索。在这两种情况下，都必须事先指定正确的对称组。但是，通常不能预测哪个对称群是通往基态的正确的群体。因此，我们引入了一种有利于对称性的势能偏置方案，并且没有必要事先指定任何对称组。在这种偏见的势能表面上，高对称结构的发现速度要比公正的表面和独立于它们所属的对称群的速度快得多。对于我们的两个测试用例，$ C_ {60} $ Fullerene和Bulk Carbide，我们的加速度为25和63。在我们的数据中，我们还发现原子环境的相似性与能量的相似性之间存在明显的相关性。在低能结构中，一个物种的所有原子都倾向于具有相似的环境。
Ground state structures found in nature are in many cases of high symmetry. But structure prediction methods typically render only a small fraction of high symmetry structures. Especially for large crystalline unit cells there are many low energy defect structures. For this reason methods have been developed where either preferentially high symmetry structures are used as input or where the whole structural search is done within a certain symmetry group. In both cases it is necessary to specify the correct symmetry group beforehand. However it can in general not be predicted which symmetry group is the correct one leading to the ground state. For this reason we introduce a potential energy biasing scheme that favors symmetry and where it is not necessary to specify any symmetry group beforehand. On this biased potential energy surface, high symmetry structures will be found much faster than on an unbiased surface and independently of the symmetry group to which they belong. For our two test cases, a $C_{60}$ fullerene and bulk silicon carbide, we get a speedups of 25 and 63. In our data we also find a clear correlation between the similarity of the atomic environments and the energy. In low energy structures all the atoms of a species tend to have similar environments.
