Evaluating exchange correlation performance on structural prediction from GGA to metaGGA

The use of density functional theory in materials prediction and structural characterization is a very well-established field. We use this methodology in a high throughput framework, where thousands of materials are analyzed and classified in databases. This step has become quite standard and many databases do not discuss their most basic approximation: which exchange correlation functional has been used. While much work has been done on the functional dependency of the cell parameters and ground state space group, little is known for the internal degrees of freedom. A crystal structure can be reduced to the cell parameters and the Wyckoff positions (WPs), some of which can add additional degrees of freedom to the crystal structure. In this work we analyze the effect on the internal degrees of freedom of more than 1500 structures, both metallic and semiconductor materials from completely local functionals as LDA up to meta-GGAs using the recently introduced SCAN.