Received 7 July 2014, Accepted 29 September 2014, Published 10 November 2014 | Defang Duan, Yunxian Liu, Fubo Tian, Da Li, Xiaoli Huang, Zhonglong Zhao, Hongyu Yu, Bingbing Liu, Wenjing Tian & Tian Cui
The study investigates the high-pressure structures, metallization, and superconductivity of the recently synthesized compound (H₂S)₂H₂ using ab initio calculations. The ordered crystal structure with P1 symmetry is identified, supported by good agreement between theoretical and experimental data. The Cccm structure is favorable up to 37 GPa, with partial hydrogen bond symmetrization. Further compression above 111 GPa leads to the R3m structure, and above 180 GPa, the Im-3m structure, both of which are metallic. The predicted metallization pressure is 111 GPa, significantly lower than the suggested pressure for bulk molecular hydrogen. The Im-3m structure is predicted to have high Tc values of 191 K to 204 K at 200 GPa, among the highest reported for H₂-rich van der Waals compounds and MH₃-type hydrides. The study highlights the potential of (H₂S)₂H₂ as a high-temperature superconductor and a promising energy storage material.The study investigates the high-pressure structures, metallization, and superconductivity of the recently synthesized compound (H₂S)₂H₂ using ab initio calculations. The ordered crystal structure with P1 symmetry is identified, supported by good agreement between theoretical and experimental data. The Cccm structure is favorable up to 37 GPa, with partial hydrogen bond symmetrization. Further compression above 111 GPa leads to the R3m structure, and above 180 GPa, the Im-3m structure, both of which are metallic. The predicted metallization pressure is 111 GPa, significantly lower than the suggested pressure for bulk molecular hydrogen. The Im-3m structure is predicted to have high Tc values of 191 K to 204 K at 200 GPa, among the highest reported for H₂-rich van der Waals compounds and MH₃-type hydrides. The study highlights the potential of (H₂S)₂H₂ as a high-temperature superconductor and a promising energy storage material.