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MATTER,MATERIALS,PHYSICS A new hydrogen-rich compound may be a record-breaking superconductor Material appears to transmit electricity without resistance at a relatively high temperature BY EMILY CONOVER 7:00AM, SEPTEMBER 10, 2018 SHARE ARTICLE HELLA HYDROGEN The compound LaH10 is composed of 10 hydrogen atoms (pink) for each lanthanum atom (green)这个化合物LaH10是由10个氢原子(粉色)，和一个镧原子(绿色)组成. This hydrogen-rich material was predicted to exhibit superconductivity, evidence for which has now been found.据预测，这种富含氢的物质会表现出超导性，目前已经找到了证据 HANYU LIU SPONSOR MESSAGE赞助商信息 Superconductors are heating up, and a world record-holder may have just been dethroned. Two studies report evidence of superconductivity — the transmission of electricity without resistance — at temperatures higher than seen before. The effect appears in compounds of lanthanum and hydrogen squeezed to extremely high pressures.有两项研究报告了超导性的证据，即在比以往更高的温度下无电阻地传递电能。这种效应出现在镧和氢被挤压到极高压力的化合物中。 All known superconductors must be chilled to function, which makes them difficult to use in real-world applications.所有已知的超导体都必须冷却才能工作，这使得它们在实际应用中很难使用。 If scientists found a superconductor that worked at room temperature, the material could be integrated into electronic devices and transmission wires, potentially saving vast amounts of energy currently lost to electrical resistance.这种材料可以集成到电子设备和传输电线中，可以节省目前因电阻而损失的大量能量 So scientists are constantly on the lookout for higher-temperature superconductors. The current record-holder, hydrogen sulfide, which also must be compressed, works below 203 kelvins, or about −70° Celsius 目前的纪录保持者,硫化氢,也必须被压缩,低于203开尔文,约合70−°摄氏度(SN: 12/26/15, p. 25). The new evidence for superconductivity is based on a dramatic drop in the resistance of the lanthanum-hydrogen compounds when cooled below a certain temperature. One team of physicists found that their compound’s resistance plummeted at a temperature of 260 kelvins (−13° C), the temperature of a very cold winter day. The purported superconductivity occurred when the material had been crushed with almost 2 million times the pressure of Earth’s atmosphere by squeezing it between two diamonds. 这种所谓的超导性发生在材料被压碎时，其压力是地球大气压力的近200万倍这种挤圧是发生在两片钻石之间。Some samples even showed signs of superconductivity at higher temperatures, up to 280 kelvins (about 7° C), physicist Russell Hemley of George Washington University in Washington, D.C., and colleagues report in a study posted online August 23 at arXiv.org. Hemley first reported signs of the compound’s superconductivity in May in Madrid at a symposium on superconductivity and pressure. TAKE THE PRESSURE When crushed between two diamonds and cooled, a purported superconductor (shown here in a view through the diamonds) appears.当压碎在两颗钻石之间并冷却时，就会出现一种所谓的超导体(通过钻石可以看到)。 A.P. DROZDOV ET AL/ARXIV.ORG 2018 Another group found evidence of superconductivity in a lanthanum-hydrogen compound under chillier, but still record-breaking, conditions. The researchers crushed lanthanum and hydrogen in a diamond press to about 1.5 million times Earth’s atmospheric pressure. When cooled to about 215 kelvins (−58° C), the compound’s resistance falls sharply, physicist Mikhail Eremets of the Max Planck Institute for Chemistry in Mainz and colleagues report in a paper posted online August 21 at arXiv.org. It’s not clear what the exact structures of the chemical compounds are and whether the two groups are studying identical materials.目前尚不清楚这些化合物的确切结构，也不清楚这两组科学家是否在研究相同的材料。 Differences between the two teams’ samples might explain the temperature discrepancy.两组样品之间的差异可能解释了温度差异 By scattering X-rays from the compound, Hemley and colleagues showed that the material’s structure was consistent with LaH10, which contains 10 hydrogen atoms for every lanthanum atom. Hemley’s team had previously predicted that LaH10 would be superconducting at a relatively high temperature. The results are “very exciting,” says theoretical chemist Eva Zurek of the University at Buffalo in New York. However, the studies are not conclusive: They have not been peer reviewed and do not yet show an essential hallmark of superconductivity called the Meissner effect, in which magnetic fields are expelled from the superconducting material 它们还没有经过同行的审查，也没有显示出一种被称为“麦斯纳效应”(Meissner effect)的超导特性(SN: 8/8/15, p. 12). But the results agree with the previous theoretical predictions made by Hemley and colleagues. So, Zurek says, “I would hope and suspect that this is indeed … correct.”“我希望并怀疑这确实……是正确的。” The researchers are now working on bolstering their evidence for superconductivity. “Both groups should make more efforts to convince people,” Eremets says. The requirement of ultrahigh pressures makes the materials unlikely to be useful for applications,超高压的要求使这种材料不太可能有实用 but better understanding of high-temperature superconductivity could lead scientists to other, more practical superconductors. The potential new superconductor and the previous record-holder are both chock-full of hydrogen. Scientists are looking for superconductivity in such hydrogen-rich materials based on the prediction that pure hydrogen, when squeezed to immensely high pressures, will become a metal that is superconducting at room temperature 潜在的新超导体和之前的纪录保持者都充满了氢气。科学家们正在寻找这种富含氢的材料中的超导性。他们的预测是，纯氢被压缩到极高的压力时，在室温下会变成一种超导金属(SN: 8/20/16, p. 18). But metallic hydrogen has proven difficult to produce, requiring pressures even higher than those needed for hydrogen-rich compounds. So scientists are looking for superconductivity in hydrogen-mimicking compounds that are easier to create.因此，科学家们正在寻找更容易制造的氢模拟化合物中的超导性。 “The picture is very bright for looking at more and more of these materials and finding these astonishingly high superconducting transition temperatures,”这张照片非常明亮，因为我们可以看到越来越多的这些材料，并发现这些惊人的超导跃迁温度。 Hemley says. Citations M. Somayazulu et al. Evidence for superconductivity above 260 K in lanthanum superhydride at megabar pressures. arXiv:1808.07695. Posted August 23 2018. A.P. Drozdov et al. Superconductivity at 215 K in lanthanum hydride at high pressures. arXiv:1808.07039. Posted August 21, 2018. |
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