A New Metallic Silicon Allotrope: c-Si16

Using the structure search method combined with first-principles calculations, a new silicon allotrope with cubic symmetry, c -Si16, is proposed. To examine the stability of c -Si16 under ambient pressure, systematic calculations of its structural, mechanical, and electronic properties were performed. Mechanical and dynamic stability are demonstrated by elastic constants and phonon spectra, respectively. In addition, the band structure and density of states show that c -Si16 is a metallic silicon material, and its conductivity mainly comes from the p -orbital electrons of silicon.