Abstract
Following the suggestion that hydrogen-rich compounds, and, in particular, silane (), might be high- superconductors at moderate pressures, very recent experiments have confirmed that silane metallises and even becomes superconducting at high pressure. In this article, we present a structural characterization of compressed silane obtained with an ab initio evolutionary algorithm for crystal structure prediction. Besides the earlier molecular and chainlike structures of and symmetries, respectively, we propose two novel structures with space groups and , to be stable at 25–55 and 220–250 GPa, respectively. According to our calculations, silane becomes metallic and superconducting at 220 GPa in the layered structure, with a theoretical of 16 K. Our calculations also show that the imaginary phonons of the recently proposed generate the structure.
- Received 16 September 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.087005
©2009 American Physical Society