title: Pressure-induced stabilization and insulator-superconductor transition of BH.
abstract: Diborane (B(2)H(6)), a high energy density material, was believed to be stable in a wide P, T interval. A systematic investigation of the B-H system using the ab initio variable-composition evolutionary simulations shows that boron monohydride (BH) is thermodynamically stable and can coexist with solid B, H(2), and B(2)H(6) in a wide pressure range above 50 GPa. B(2)H(6) becomes unstable and decomposes into the Ibam phase of BH and H(2) (C2/c) at 153 GPa. The semiconducting layered Ibam structure of BH at 168 GPa transforms into a metallic phase with space group P6/mmm and a 3D topology with strong B-B and B-H covalent bonds. The Ibam-P6/mmm transformation pathway suggests the possibility of obtaining the metastable Pbcm phase on cold decompression of the P6/mmm phase. The electron-phonon coupling calculations indicate that P6/mmm-BH is a phonon-mediated superconductor with a critical temperature of superconductivity (T(c)) of 14.1-21.4 K at 175 GPa.
authors.affiliation: School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004, People's Republic of China. chaohao.hu@guet.edu.cn
authors.forename: Chao-Hao
authors.initials: CH
authors.lastname: Hu
authors.forename: Artem R
authors.initials: AR
authors.lastname: Oganov
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhu
authors.forename: Guang-Rui
authors.initials: GR
authors.lastname: Qian
authors.forename: Gilles
authors.initials: G
authors.lastname: Frapper
authors.forename: Andriy O
authors.initials: AO
authors.lastname: Lyakhov
authors.forename: Huai-Ying
authors.initials: HY
authors.lastname: Zhou