Electronic structure of C-60 simple cubic phase by full-potential mixed-basis band calculation

An electronic structure calculation with full-potential and all-electron ab initio formalism is performed for hypothetical low-temperature simple cubic phases (Pn (3) over bar and Pa (3) over bar space groups) of C-60 molecular crystal, in which every molecule is orientationally freezed. The degeneracies at special k-points, the magnitudes of energy gaps, and the widths of bands have been found to be sensitive to the orientation of the fullerenes in the crystal. Our result suggests that the structure with Pa (3) over bar space group with -22 degrees rotation around [111] directions, which David et al. proposed, is more stable compared to the structure with Pn (3) over bar space group with the same rotation angle.