含碳硫氢化物的室温超导性,Nature

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含碳硫氢化物的室温超导性
Nature ( IF 50.5 ) Pub Date : 2020-10-14 , DOI: 10.1038/s41586-020-2801-z
Elliot Snider ₁ , Nathan Dasenbrock-Gammon ₂ , Raymond McBride ₁ , Mathew Debessai ₃ , Hiranya Vindana ₂ , Kevin Vencatasamy ₂ , Keith V Lawler ₄ , Ashkan Salamat ₅ , Ranga P Dias _{1,

2}

Affiliation

实验物理学中长期存在的挑战之一是观察室温超导性1,2。最近，在高压下的几个系统中报道了富氢材料中的高温常规超导性 3-5。导致室温超导性的一个重要发现是硫化氢 (H2S) 到 H3S 的压力驱动歧化，在 155 吉帕斯卡 3,6 时确认的转变温度为 203 开尔文。H2S 和 CH4 都容易与氢混合，在较低压力下形成客体结构 7，并且在 4 吉帕斯卡下具有相当的尺寸。通过在低压下将甲烷引入 H2S + H2 的 H3S 前体混合物中，允许在富含 H2 夹杂物的大量范德华固体组合内进行分子交换；这些客体结构成为极端条件下超导化合物的基石。在这里，我们报告了从元素前体开始的光化学转化的碳质硫氢化物系统中的超导性，在 267 ± 10 吉帕斯卡下达到的最大超导转变温度为 287.7 ± 1.2 开尔文（约 15 摄氏度）。在 140 至 275 吉帕斯卡的宽压力范围内，在金刚石砧座单元中观察到超导状态，转变温度在 220 吉帕斯卡以上时急剧上升。超导性是通过观察零电阻、高达 190 吉帕的磁化率以及在高达 9 特斯拉的外部磁场下降低转变温度来建立的，根据金茨堡-朗道模型，在零温度下，上临界磁场约为 62 特斯拉。氢的光、量子性质限制了通过 X 射线散射技术对系统的结构和化学计量测定，但拉曼光谱用于探测金属化之前的化学和结构转变。在我们的三元系统中引入化学调谐可以在较低压力下保持室温超导的特性。

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Room-temperature superconductivity in a carbonaceous sulfur hydride

One of the long-standing challenges in experimental physics is the observation of room-temperature superconductivity1,2. Recently, high-temperature conventional superconductivity in hydrogen-rich materials has been reported in several systems under high pressure3-5. An important discovery leading to room-temperature superconductivity is the pressure-driven disproportionation of hydrogen sulfide (H2S) to H3S, with a confirmed transition temperature of 203 kelvin at 155 gigapascals3,6. Both H2S and CH4 readily mix with hydrogen to form guest-host structures at lower pressures7, and are of comparable size at 4 gigapascals. By introducing methane at low pressures into the H2S + H2 precursor mixture for H3S, molecular exchange is allowed within a large assemblage of van der Waals solids that are hydrogen-rich with H2 inclusions; these guest-host structures become the building blocks of superconducting compounds at extreme conditions. Here we report superconductivity in a photochemically transformed carbonaceous sulfur hydride system, starting from elemental precursors, with a maximum superconducting transition temperature of 287.7 ± 1.2 kelvin (about 15 degrees Celsius) achieved at 267 ± 10 gigapascals. The superconducting state is observed over a broad pressure range in the diamond anvil cell, from 140 to 275 gigapascals, with a sharp upturn in transition temperature above 220 gigapascals. Superconductivity is established by the observation of zero resistance, a magnetic susceptibility of up to 190 gigapascals, and reduction of the transition temperature under an external magnetic field of up to 9 tesla, with an upper critical magnetic field of about 62 tesla according to the Ginzburg-Landau model at zero temperature. The light, quantum nature of hydrogen limits the structural and stoichiometric determination of the system by X-ray scattering techniques, but Raman spectroscopy is used to probe the chemical and structural transformations before metallization. The introduction of chemical tuning within our ternary system could enable the preservation of the properties of room-temperature superconductivity at lower pressures.

更新日期：2020-10-14

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