Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5
Electronic in-plane symmetry breaking at field-tuned quantum criticality in CeRhIn5
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DOI：
10.1038/nature23315
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发表时间：
2017-08-17
期刊：
影响因子：
64.8
通讯作者：
Moll, P. J. W.
中科院分区：
文献类型：
--
作者：
Ronning, F.;Helm, T.;Moll, P. J. W.
电子向列型材料的特征在于，与底层晶格相比，电子系统的对称性较低，类似于向列型液晶中没有平移顺序的定向排列（1）。这种超导相出现在铜基和铁基高温超导体中（2-4），它们在建立超导性中的作用仍然是一个悬而未决的问题。向列性可能积极参与，与超导性合作或竞争，也可能偶然出现在这样的系统中。在这里，我们提出了实验证据，在一个重费米子超导体，CeRhIn 5（参考文献5）的波动的相位特性。我们观察到一个磁场诱导的状态在附近的一个场调谐的反铁磁量子临界点在H-c约为50特斯拉。该相出现在近似为28特斯拉的面外临界场H* 之上，并且其特征在于在存在小的面内场分量的情况下具有显著的面内电阻率各向异性。面内对称性破缺与底层晶格几乎没有明显的联系，这一点可以通过H* 处的磁致伸缩异常的小幅度来证明。此外，没有出现异常的磁矩，这表明在这个领域的范围内没有变磁性。在原型重费米子超导体中的超导行为的出现突出了向列性和非常规超导性的相互关系，表明向列性在相关材料中是常见的。
Electronic nematic materials are characterized by a lowered symmetry of the electronic system compared to the underlying lattice, in analogy to the directional alignment without translational order in nematic liquid crystals(1). Such nematic phases appear in the copper-and iron-based high-temperature superconductors(2-4), and their role in establishing superconductivity remains an open question. Nematicity may take an active part, cooperating or competing with superconductivity, or may appear accidentally in such systems. Here we present experimental evidence for a phase of fluctuating nematic character in a heavy-fermion superconductor, CeRhIn5 (ref. 5). We observe a magnetic-field-induced state in the vicinity of a field-tuned antiferromagnetic quantum critical point at H-c approximate to 50 tesla. This phase appears above an out-of-plane critical field H* approximate to 28 tesla and is characterized by a substantial in-plane resistivity anisotropy in the presence of a small in-plane field component. The in-plane symmetry breaking has little apparent connection to the underlying lattice, as evidenced by the small magnitude of the magnetostriction anomaly at H*. Furthermore, no anomalies appear in the magnetic torque, suggesting the absence of metamagnetism in this field range. The appearance of nematic behaviour in a prototypical heavy-fermion superconductor highlights the interrelation of nematicity and unconventional superconductivity, suggesting nematicity to be common among correlated materials.