Field-Induced Quantum Critical Point and Nodal Superconductivity in the Heavy-Fermion Superconductor Ce2PdIn8
Field-Induced Quantum Critical Point and Nodal Superconductivity in the Heavy-Fermion Superconductor Ce2PdIn8
复制标题
重费米子超导体 Ce2PdIn8 中场致量子临界点和节点超导性
DOI：
10.1103/physrevx.1.011010
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发表时间：
2011-09-15
影响因子：
12.5
通讯作者：
Li, S. Y.
中科院分区：
文献类型：
--
作者：
Dong, J. K.;Zhang, H.;Li, S. Y.
磁性和超导性之间的相互作用一直是非常规超导体的核心问题。虽然动态磁性可能是电子配对的来源，但静态磁性通常被认为是与超导性竞争的。从这个意义上说，重费米子超导体CeCoIn5中Q相、耦合自旋密度波序和超导性的观察是非常令人费解的。这个Q相是否起源于新颖的富尔德-费雷尔-拉金-奥夫钦尼科夫态，目前争论激烈。本文报道了新发现的重费米子超导体Ce2PdIn8在50 mK下的电阻率和热导率的研究。我们发现Ce2PdIn8在临界场Hc2上有一个不寻常的场致量子临界点，并且在Ce2PdIn8中发现了非常规的节点超导性。热导率k(H)/T在Hc2附近的跳跃表明在低温下发生了一类一阶相变。这些结果模拟了CeCoIn5中Q相的特征，这意味着Ce2PdIn8是另一个有希望研究奇异Q相和FFLO态的化合物。CeCoIn5和Ce2PdIn8的比较可能有助于澄清Q相的起源。
The interplay between magnetism and superconductivity has been a central issue in unconventional superconductors. While the dynamic magnetism could be the source of electron pairing, the static magnetism is generally believed to compete with superconductivity. In this sense, the observation of Q phase, the coupled spin-density wave order and superconductivity, in the heavy-fermion superconductor CeCoIn5 is very puzzling. Whether this Q phase origins from the novel Fulde-Ferrel-Larkin-Ovchinnikov state is under hot debate. Here we report the resistivity and thermal conductivity study of a newly discovered heavy-fermion superconductor Ce2PdIn8 down to 50 mK. We find an unusual field-induced quantum critical point at the upper critical field Hc2 and unconventional nodal superconductivity in Ce2PdIn8. The jump of thermal conductivity k(H)/T near Hc2 suggests a first-order-like phase transition at low temperatures. These results mimic the features of the Q phase in CeCoIn5, implying that Ce2PdIn8 is another promising compound to investigate the exotic Q phase and FFLO state. The comparison between CeCoIn5 and Ce2PdIn8 may help to clarify the origin of the Q phase.