Possible “Magnéli” Phases and Self-Alloying in the Superconducting Sulfur Hydride

2015/12/31 by Ryosuke Akashi, Wataru Sano, Ryotaro Arita +1 · 2 citations
Chemistry · Earth and Planetary Sciences · Physics and Astronomy · #Advanced Chemical Physics Studies #Chemistry #Condensed matter physics #Crystal structure #Crystallography #Enthalpy #High-pressure geophysics and materials #Hydride #Materials science #Metal #Metallurgy #Metastability #Physics #Quantum, superfluid, helium dynamics #Sulfur #Superconductivity #Thermodynamics #cond-mat.supr-con

paper · pdf · doi:10.1103/physrevlett.117.075503

published as Phys. Rev. Lett. 117, 075503 (2016) · 11 pages, 10 figures. ver2: Tc calculation and Xray simulation added

openalex publication_date 2016/08/10 · arxiv created 2016/08/11 · arxiv updated 2016/08/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We theoretically give an infinite number of metastable crystal structures for the superconducting sulfur hydride H_xS under pressure. Previously predicted crystalline phases of H₂S and H₃S have been thought to have important roles for experimentally observed low and high T_c, respectively. The newly found structures are long-period modulated crystals where slablike H₂S and H₃S regions intergrow on a microscopic scale. The extremely small formation enthalpy for the H₂S-H₃S boundary indicated by first-principles calculations suggests possible alloying of these phases through the formation of local H₃S regions. The modulated structures and gradual alloying transformations between them not only explain the peculiar pressure dependence of T_c in sulfur hydride observed experimentally, but also could prevail in the experimental samples under various compression schemes.

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Cited by

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• Electrical transport measurements for superconducting sulfur hydrides using boron-doped diamond electrodes on beveled diamond anvil
• First-principles calculation of coherence length and penetration depth based on density functional theory for superconductors