title: The metallization and superconductivity of dense hydrogen sulfide.
abstract: Hydrogen sulfide (H2S) is a prototype molecular system and a sister molecule of water (H2O). The phase diagram of solid H2S at high pressures remains largely unexplored arising from the challenges in dealing with the pressure-induced weakening of S-H bond and larger atomic core difference between H and S. Metallization is yet achieved for H2O, but it was observed for H2S above 96 GPa. However, the metallic structure of H2S remains elusive, greatly impeding the understanding of its metallicity and the potential superconductivity. We have performed an extensive structural study on solid H2S at pressure ranges of 10-200 GPa through an unbiased structure prediction method based on particle swarm optimization algorithm. Besides the findings of candidate structures for nonmetallic phases IV and V, we are able to establish stable metallic structures violating an earlier proposal of elemental decomposition into sulfur and hydrogen [R. Rousseau, M. Boero, M. Bernasconi, M. Parrinello, and K. Terakura, Phys. Rev. Lett. 85, 1254 (2000)]. Our study unravels a superconductive potential of metallic H2S with an estimated maximal transition temperature of ∼80 K at 160 GPa, higher than those predicted for most archetypal hydrogen-containing compounds (e.g., SiH4, GeH4, etc.).
authors.affiliation: School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, People's Republic of China.
authors.forename: Yinwei
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, People's Republic of China.
authors.forename: Jian
authors.initials: J
authors.lastname: Hao
authors.affiliation: Department of Physics and Engineering Physics, University of Saskatchewan, Saskatchewan S7N 5E2, Canada.
authors.forename: Hanyu
authors.initials: H
authors.lastname: Liu
authors.affiliation: School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, People's Republic of China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, People's Republic of China.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Ma