title: High-pressure crystal structures and superconductivity of Stannane (SnH4).
abstract: There is great interest in the exploration of hydrogen-rich compounds upon strong compression where they can become superconductors. Stannane (SnH(4)) has been proposed to be a potential high-temperature superconductor under pressure, but its high-pressure crystal structures, fundamental for the understanding of superconductivity, remain unsolved. Using an ab initio evolutionary algorithm for crystal structure prediction, we propose the existence of two unique high-pressure metallic phases having space groups Ama2 and P6(3)/mmc, which both contain hexagonal layers of Sn atoms and semimolecular (perhydride) H(2) units. Enthalpy calculations reveal that the Ama2 and P6(3)/mmc structures are stable at 96-180 GPa and above 180 GPa, respectively, while below 96 GPa SnH(4) is unstable with respect to elemental decomposition. The application of the Allen-Dynes modified McMillan equation reveals high superconducting temperatures of 15-22 K for the Ama2 phase at 120 GPa and 52-62 K for the P6(3)/mmc phase at 200 GPa.
authors.affiliation: National Laboratory of Superhard Materials, Jilin University, Changchun 130012, PR China.
authors.forename: Guoying
authors.initials: G
authors.lastname: Gao
authors.forename: Artem R
authors.initials: AR
authors.lastname: Oganov
authors.forename: Peifang
authors.initials: P
authors.lastname: Li
authors.forename: Zhenwei
authors.initials: Z
authors.lastname: Li
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Tian
authors.initials: T
authors.lastname: Cui
authors.forename: Yanming
authors.initials: Y
authors.lastname: Ma
authors.forename: Aitor
authors.initials: A
authors.lastname: Bergara
authors.forename: Andriy O
authors.initials: AO
authors.lastname: Lyakhov
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Iitaka
authors.forename: Guangtian
authors.initials: G
authors.lastname: Zou