X-ray diffraction and equation of state of the C-S-H room-temperature superconductor.
X-ray diffraction and equation of state of the C-S-H room-temperature superconductor.
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DOI：
10.1063/5.0064750
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
Anmol Lamichhane;Ravhi S Kumar;M. Ahart;N. Salke;N. Dasenbrock-Gammon;Elliot Snider;Y. Meng;
中科院分区：
文献类型：
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作者：
Anmol Lamichhane;Ravhi S Kumar;M. Ahart;N. Salke;N. Dasenbrock-Gammon;Elliot Snider;Y. Meng;
X射线衍射表明，最近发现的碳质硫氢化物（C-S-H）室温超导体的结构是从以前建立的货车范德华化合物中发现的H2 S-H2和CH 4-H2系统。通过光化学合成技术产生超导相的晶体，导致在267 GPa下的超导临界温度Tc为288 K。在超导相的压力范围内，从124到178 GPa测量的X射线衍射图案与从（H2S）2 H2和（CH 4）2 H2确定的Al 2Cu型得到的正交结构一致，该正交结构不同于在这些压力下对S-H系统预测和观察到的正交结构。C-S-H化合物的形成和稳定性可以根据H2S和CH 4组分的有效体积的密切相似性来理解，并且在较高的压力下可以形成更致密的含碳S-H相。这些结果对于理解兆巴压力下C-S-H系统中发现的非常高的超导Tc至关重要。
X-ray diffraction indicates that the structure of the recently discovered carbonaceous sulfur hydride (C-S-H) room-temperature superconductor is derived from previously established van der Waals compounds found in the H2S-H2 and CH4-H2 systems. Crystals of the superconducting phase were produced by a photochemical synthesis technique, leading to the superconducting critical temperature Tc of 288 K at 267 GPa. X-ray diffraction patterns measured from 124 to 178 GPa, within the pressure range of the superconducting phase, are consistent with an orthorhombic structure derived from the Al2Cu-type determined for (H2S)2H2 and (CH4)2H2 that differs from those predicted and observed for the S-H system at these pressures. The formation and stability of the C-S-H compound can be understood in terms of the close similarity in effective volumes of the H2S and CH4 components, and denser carbon-bearing S-H phases may form at higher pressures. The results are crucial for understanding the very high superconducting Tc found in the C-S-H system at megabar pressures.