CrAs--第一个Cr基化合物超导体的发现  

The discovery of superconductivity in Cr-based compounds

作　　者：吴伟[1] 程金光[1] 雒建林[1] 

机构地区：[1]中国科学院物理研究所,北京100190

出　　处：《物理》2016年第2期73-79,共7页Physics

摘　　要：非常规超导体自发现以来便引起了凝聚态物理学家的广泛兴趣,诸如重费米子超导体,铜基高温超导体和铁基高温超导体等。这类超导体的一个基本特征是,当长程反铁磁序被抑制时会出现超导现象。而要破坏长程磁有序,除了掺杂不同元素以引入电荷载流子或者化学压力外,物理加压也是一种有效的调控手段。文章将介绍第一个Cr基化合物超导体——CrAs单晶通过物理加压首次实现超导电性的过程。当压力为8 kbar时,超导临界温度出现在2K,这时发生在常压下265 K的一级反铁磁相变被完全压制。在CrAs体系中,超导与反铁磁序之间的竞争关系说明CrAs是非常规超导体。CrAs的超导也为发现新型超导体打开了一扇大门。One of the most common features of unconventional superconducting systems such as heavy fermionso high transition-temperature cuprates and iron pnictides is that the super- conductivity emerges in the vicinity of a long-range antiferromagneticaUy ordered state. In addi- tion to doping charge carriers, the application of external pressure is an effective and clean ap- proach to induce unconventional superconductivity near a magnetic quantum critical point. Here we report on the discovery of superconductivity on the verge of antiferromagnetic order in CrAs via the application of external pressure. Bulk superconductivity with Tc=2 K emerges at the critical pressure Tc=8 kbar, where the first-order antiferromagnetic transition at TN=265 K under ambient pressure is completely suppressed. The close proximity of superconductivity to an antiferromagnetic order suggests an uncon- ventional pairing mechanism for CrAs. The present finding opens a new avenue in the search for novel superconductors in Cr and other transition metal based systems.

关 键 词：超导 压力 Cr基化合物 量子临界 

分 类 号：O511.3[一般工业技术—材料科学与工程]