Heavy-Fermion Superconductivity in the Quadrupole Ordered State of PrV2Al20
Heavy-Fermion Superconductivity in the Quadrupole Ordered State of PrV2Al20
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DOI：
10.1103/physrevlett.113.267001
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发表时间：
2014-12-23
影响因子：
8.6
通讯作者：
Nakatsuji, Satoru
中科院分区：
文献类型：
--
作者：
Tsujimoto, Masaki;Matsumoto, Yosuke;Nakatsuji, Satoru
PrV 2Al 20是一个罕见的重费米子系统的例子，它是基于传导电子和立方伽马（3）基态偶极的四极矩之间的强杂化。在这里，我们报告说，高品质的单晶PrV 2Al 20表现出超导电性在Tc = 50 mK的反铁四极有序状态在环境压力下。超导性的重费米子特征是明显的，从类似于0.3 J/mol K-2的Δ C/T的比热跃变和类似于140的有效质量m*/m（0）从上临界场的温度依赖性估计。此外，高质量的单晶体在T-Q = 0.75 K和T* = 0.65 K处表现出与γ（3）二重态的四极和八极自由度相关的双跃迁。在有序状态下，比热C/T表现出T-3依赖性，表明与四极序、八极序或两者相关联的无隙模式。超导电性对杂质的强烈敏感性表明了由于显著的四极涨落而导致的非常规特征。
PrV2Al20 is a rare example of a heavy-fermion system based on strong hybridization between conduction electrons and nonmagnetic quadrupolar moments of the cubic Gamma(3) ground doublet. Here, we report that a high-quality single crystal of PrV2Al20 exhibits superconductivity at T-c = 50 mK in the antiferroquadrupole-ordered state under ambient pressure. The heavy-fermion character of the superconductivity is evident from the specific heat jump of Delta C/T similar to 0.3 J/mol K-2 and the effective mass m*/m(0) similar to 140 estimated from the temperature dependence of the upper critical field. Furthermore, the high-quality single crystals exhibit double transitions at T-Q = 0.75 K and T* = 0.65 K associated with quadrupole and octupole degrees of freedom of the Gamma(3) doublet. In the ordered state, the specific heat C/T shows a T-3 dependence, indicating the gapless mode associated with the quadrupole order, the octupole order, or both. The strong sensitivity to impurity of the superconductivity suggests unconventional character due to significant quadrupolar fluctuations.