title: Stability and properties of the Ru-H system at high pressure.
abstract: We report on a first-principles study of the phase diagram, structures and properties of the Ru-H system in the H-rich regime over a wide range of pressures. The results show that RuH is thermodynamically stable and can coexist with RuH3 and RuH6 under pressure. RuH and RuH3 stoichiometries exhibit metallic character as a result of notable band structures, while RuH6 is a semiconductor. Strikingly, some hydrogen atoms pairwise couple into H2 units in the RuH6 compound. An estimation of superconducting transition temperature Tc is carried out by applying the Allen-Dynes modified McMillan equation for Fm3[combining macron]m (RuH), Pm3[combining macron]m (RuH3), and Pm3[combining macron]n (RuH3) structures and the resulting Tc reaches 0.41, 3.57 and 1.25 K at different pressures, respectively.
authors.affiliation: State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, P. R. China. cuitian@jlu.edu.cn.
authors.forename: Yunxian
authors.initials: Y
authors.lastname: Liu
authors.forename: Defang
authors.initials: D
authors.lastname: Duan
authors.forename: Fubo
authors.initials: F
authors.lastname: Tian
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Ma
authors.forename: Da
authors.initials: D
authors.lastname: Li
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Huang
authors.forename: Bingbing
authors.initials: B
authors.lastname: Liu
authors.forename: Tian
authors.initials: T
authors.lastname: Cui