Superconductivity of novel tin hydrides (Sn n H m ) under pressure

With the motivation of discovering high-temperature superconductors, evolutionary algorithm USPEX is employed to search for all stable compounds in the Sn-H system. In addition to the traditional SnH 4 , new hydrides SnH 8 , SnH 12 and SnH 14 are found to be thermodynamically stable at high pressure. Dynamical stability and superconductivity of tin hydrides are systematically investigated. I m2-SnH 8 , C2/m-SnH 12 and C2/m-SnH 14 exhibit higher superconducting transition temperatures of 81, 93 and 97 K compared to the traditional compound SnH4 with T c of 52 K at 200 GPa. An interesting bent H 3 –group in I m2-SnH 8 and novel linear H in C2/m-SnH 12 are observed. All the new tin hydrides remain metallic over their predicted range of stability. The intermediate-frequency wagging and bending vibrations have more contribution to electron-phonon coupling parameter than high-frequency stretching vibrations of H2 and H3.