摘要
Hydrogen is expected to be a metal at sufficient high pressures[1]while it can also be a high temperature superconductor based on BCS theory because of its high Debye temperature arising from the light mass of hydrogen[2].Since it is very challenging to reach the pressure for the hydrogen metallization,the “chemically precompressed” hydrogen-rich compounds were in turn proposed[3,4]to realize high temperature superconductivity at lower pressures.The experimental discovery of high temperature superconductivity[5]in SH3 has greatly stimulated efforts to explore new hydrogen-rich superconductors,such as in rare earth polyhydrides[6,7].
氢是周期表里质量最轻的元素,早期理论预测氢在超高压条件可以呈现固体金属态,根据BCS电声耦合理论推测金属氢可能具有高温超导特性.然而实现纯氢的金属化需要很高的压力,技术复杂极具挑战.富氢化合物可以对氢提供“化学预压缩”,有可能在较低压力实现以氢为主的金属化和超导,目前实验上已经在硫、稀土和碱土金属等富氢化物材料发现高温超导现象.本文作者运用自行研发的先进的超高压和激光加热一体化的极端条件集成技术,在~220 GPa、2000 K的高压高温条件下成功合成了高质量的锆富氢新化合物,并在锆富氢化合物中发现高压在位诱导的临界转变温度(T;)高达71 K的超导现象,这是首次在4d过渡金属氢化物发现高温超导.
基金
supported by the National Natural Science Foundation of China,Ministry of Science and Technology of the People’s Republic of China
Chinese Academy of Sciences through Research Projects(2018YFA0305700,11921004,and XDB33010200)。
