Synthesis of molecular metallic barium superhydride: pseudocubic BaH12

Wuhao Chen; Dmitrii V Semenok; Alexander G Kvashnin; Xiaoli Huang; Ivan A Kruglov; Michele Galasso; Hao Song; Defang Duan; Alexander F Goncharov; Vitali B Prakapenka; Artem R Oganov; Tian Cui

doi:10.1038/s41467-020-20103-5

Synthesis of molecular metallic barium superhydride: pseudocubic BaH₁₂

Nat Commun. 2021 Jan 11;12(1):273. doi: 10.1038/s41467-020-20103-5.

Authors

Wuhao Chen^#¹, Dmitrii V Semenok^#², Alexander G Kvashnin^#², Xiaoli Huang³, Ivan A Kruglov^{4

5}, Michele Galasso², Hao Song¹, Defang Duan¹, Alexander F Goncharov⁶, Vitali B Prakapenka⁷, Artem R Oganov⁸, Tian Cui^{9

10}

Affiliations

¹ State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, China.
² Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Moscow, 143026, Russia.
³ State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, China. huangxiaoli@jlu.edu.cn.
⁴ Moscow Institute of Physics and Technology, 9 Institutsky Lane, Dolgoprudny, 141700, Russia.
⁵ Dukhov Research Institute of Automatics (VNIIA), Moscow, 127055, Russia.
⁶ Earth and Planets Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC, 20015, USA.
⁷ Center for Advanced Radiation Sources, The University of Chicago, 5640 South Ellis Avenue, Chicago, IL, 60637, USA.
⁸ Skolkovo Institute of Science and Technology, Skolkovo Innovation Center, 3 Nobel Street, Moscow, 143026, Russia. a.oganov@skoltech.ru.
⁹ State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun, 130012, China. cuitian@jlu.edu.cn.
¹⁰ School of Physical Science and Technology, Ningbo University, Ningbo, 315211, China. cuitian@jlu.edu.cn.

^# Contributed equally.

Abstract

Following the discovery of high-temperature superconductivity in the La-H system, we studied the formation of new chemical compounds in the barium-hydrogen system at pressures from 75 to 173 GPa. Using in situ generation of hydrogen from NH₃BH₃, we synthesized previously unknown superhydride BaH₁₂ with a pseudocubic (fcc) Ba sublattice in four independent experiments. Density functional theory calculations indicate close agreement between the theoretical and experimental equations of state. In addition, we identified previously known P6/mmm-BaH₂ and possibly BaH₁₀ and BaH₆ as impurities in the samples. Ab initio calculations show that newly discovered semimetallic BaH₁₂ contains H₂ and H₃^- molecular units and detached H₁₂ chains which are formed as a result of a Peierls-type distortion of the cubic cage structure. Barium dodecahydride is a unique molecular hydride with metallic conductivity that demonstrates the superconducting transition around 20 K at 140 GPa.

Abstract

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