Superconductivity in hydrogen dominant materials: Silane

The metallization of hydrogen directly would require pressure in excess of 400 gigapascals ( GPa), out of the reach of present experimental techniques. The dense group IVa hydrides attract considerable attention because hydrogen in these compounds is chemically precompressed and a metallic state is expected to be achievable at experimentally accessible pressures. We report the transformation of insulating molecular silane to a metal at 50 GPa, becoming superconducting at a transition temperature of T-c = 17 kelvin at 96 and 120 GPa. The metallic phase has a hexagonal close- packed structure with a high density of atomic hydrogen, creating a three- dimensional conducting network. These experimental findings support the idea of modeling metallic hydrogen with hydrogen- rich alloy.