Sarrao J L, Morales L A, Thompson J D, Scott B L, Stewart G R, Wastin F, Rebizant J, Boulet P, Colineau E, Lander G H
Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
Nature. 2002 Nov 21;420(6913):297-9. doi: 10.1038/nature01212.
Plutonium is a metal of both technological relevance and fundamental scientific interest. Nevertheless, the electronic structure of plutonium, which directly influences its metallurgical properties, is poorly understood. For example, plutonium's 5f electrons are poised on the border between localized and itinerant, and their theoretical treatment pushes the limits of current electronic structure calculations. Here we extend the range of complexity exhibited by plutonium with the discovery of superconductivity in PuCoGa5. We argue that the observed superconductivity results directly from plutonium's anomalous electronic properties and as such serves as a bridge between two classes of spin-fluctuation-mediated superconductors: the known heavy-fermion superconductors and the high-T(c) copper oxides. We suggest that the mechanism of superconductivity is unconventional; seen in that context, the fact that the transition temperature, T(c) approximately 18.5 K, is an order of magnitude greater than the maximum seen in the U- and Ce-based heavy-fermion systems may be natural. The large critical current displayed by PuCoGa5, which comes from radiation-induced self damage that creates pinning centres, would be of technological importance for applied superconductivity if the hazardous material plutonium were not a constituent.
钚是一种在技术应用和基础科学研究方面都具有重要意义的金属。然而，人们对钚的电子结构了解甚少，而其电子结构又直接影响着钚的冶金性能。例如，钚的5f电子处于局域化和巡游态的边界，对它们的理论处理已达到了当前电子结构计算的极限。在此，我们通过在PuCoGa5中发现超导现象，拓展了钚所展现出的复杂程度范围。我们认为，所观测到的超导现象直接源于钚的反常电子特性，因此它成为了两类自旋涨落介导的超导体之间的桥梁：已知的重费米子超导体和高温铜氧化物超导体。我们认为超导机制是非传统的；在这种背景下，转变温度T(c)约为18.5 K，比基于U和Ce的重费米子体系中所观测到的最高值高出一个数量级这一事实可能是合理的。如果不是因为含有危险物质钚，PuCoGa5所表现出的大临界电流（源于辐射诱导的自损伤产生钉扎中心）对于应用超导来说将具有重要的技术意义。
