Superconductivity at 250 K in lanthanum hydride under high pressures
Superconductivity at 250 K in lanthanum hydride under high pressures
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DOI：
10.1038/s41586-019-1201-8
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发表时间：
2019-05-23
期刊：
影响因子：
64.8
通讯作者：
Eremets, M. I.
中科院分区：
文献类型：
--
作者：
Drozdov, A. P.;Kong, P. P.;Eremets, M. I.
随着H3S中203开尔文超导性的发现(1)，人们的注意力又回到了传统超导体上，这些超导体的性质可以用Bardeen-Cooper-Schrieffer和migdahl - eliashberg理论来描述。尽管这些理论预测了具有某些有利特性（如高频晶格振动）的金属在室温下超导的可能性，但它们不足以指导设计或预测新的超导材料的特性。基于密度泛函理论的第一性原理计算实现了这样的预测，并提出了一种新的超导氢化物家族，它具有笼状结构，其中主原子（钙、钇、镧）位于由氢原子形成的笼状结构的中心（2-4）。对于LaH10和YH10，预计在240和320开尔文之间的临界温度和兆巴压力下发生超导性（3-6）。在这里，我们报道了在170千兆帕斯卡的压力下，LaH10的barm结构在Fm(3)内具有临界温度约为250开尔文的超导性。据我们所知，这是迄今为止在超导材料中确认的最高临界温度。通过观察到零电阻、同位素效应和在外磁场作用下临界温度的降低，证明了超导性，这表明在零温度下临界磁场的上限约为136特斯拉。与之前的最高临界温度(1)相比，大约50开尔文的提高是在不久的将来实现室温超导目标的令人鼓舞的一步。
With the discovery(1) of superconductivity at 203 kelvin in H3S, attention returned to conventional superconductors with properties that can be described by the Bardeen-Cooper-Schrieffer and the Migdal-Eliashberg theories. Although these theories predict the possibility of room-temperature superconductivity in metals that have certain favourable properties-such as lattice vibrations at high frequencies-they are not sufficient to guide the design or predict the properties of new superconducting materials. First-principles calculations based on density functional theory have enabled such predictions, and have suggested a new family of superconducting hydrides that possess a clathrate-like structure in which the host atom (calcium, yttrium, lanthanum) is at the centre of a cage formed by hydrogen atoms(2-4). For LaH10 and YH10, the onset of superconductivity is predicted to occur at critical temperatures between 240 and 320 kelvin at megabar pressures(3-6). Here we report superconductivity with a critical temperature of around 250 kelvin within the Fm (3) over barm structure of LaH10 at a pressure of about 170 gigapascals. This is, to our knowledge, the highest critical temperature that has been confirmed so far in a superconducting material. Superconductivity was evidenced by the observation of zero resistance, an isotope effect, and a decrease in critical temperature under an external magnetic field, which suggested an upper critical magnetic field of about 136 tesla at zero temperature. The increase of around 50 kelvin compared with the previous highest critical temperature(1) is an encouraging step towards the goal of achieving room-temperature superconductivity in the near future.