Strong-coupling superconductivity in the nickel-based oxypnictide LaNiAsO1-xFx
Strong-coupling superconductivity in the nickel-based oxypnictide LaNiAsO1-xFx
复制标题
镍基氮氧化物LaNiAsO1-xFx的强耦合超导性
DOI：
10.1103/physrevb.78.060504
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发表时间：
2008-08-01
影响因子：
3.7
通讯作者：
Luo, Jianlin
中科院分区：
文献类型：
--
作者：
Li, Zheng;Chen, Gengfu;Luo, Jianlin
通过固相反应合成了一系列x=0-0.15的层状镍基LaNiAsO(1-x)F(x)化合物。纯LaNiAsO在T(c)接近2.75 K时表现出大块超导性。氧与氟的部分取代使转变温度升高到3.8 K左右。LaNiAsO(0.9)F（0.1）样品在临界温度下表现出明显的超导转变和明显的比热跳变。比热跳变的幅度远远大于弱耦合BCS理论的预期值，表明该超导体处于强耦合状态。此外，对于单带s波或d波超导体，比热的温度依赖性与理论结果有很大的偏差，但表现出多隙的特征。
A series of layered nickel-based LaNiAsO(1-x)F(x) compounds with x=0-0.15 are synthesized by solid-state reactions. The pure LaNiAsO exhibits bulk superconductivity with T(c)similar to 2.75 K. Partial substitution of oxygen with fluorine increases the transition temperature to similar to 3.8 K. The LaNiAsO(0.9)F(0.1) sample shows a sharp superconducting transition and a sharp specific-heat jump at the critical temperature. The magnitude of the specific-heat jump is much larger than that expected from the weak-coupling BCS theory, indicating that this superconductor is in the strong-coupling regime. Furthermore, the temperature dependence of the specific heat deviates strongly from the theoretical result for the single-band s- or d-wave superconductor but shows a characteristic feature of multigap.