Localized-to-itinerant transition preceding antiferromagnetic quantum critical point and gapless superconductivity in CeRh0.5Ir0.5In5
Localized-to-itinerant transition preceding antiferromagnetic quantum critical point and gapless superconductivity in CeRh0.5Ir0.5In5
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CeRh0.5Ir0.5In5 中反铁磁量子临界点之前的局域到巡回转变和无间隙超导
DOI：
10.1038/s42005-020-00418-x
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发表时间：
2020-08-27
影响因子：
5.5
通讯作者：
Zheng, Guo-qing
中科院分区：
文献类型：
--
作者：
Kawasaki, Shinji;Oka, Toshihide;Zheng, Guo-qing
从相关电子化合物的研究中提出的一个基本问题，其中重费米子系统是原型，是需要了解量子临界点（QCP）附近的状态物理。在QCP中，磁序被连续抑制到零温度，并且经常出现非常规的超导性。在这里，我们报告的压力（P）依赖115在核四极共振（NQR）测量重费米子反铁磁体CeRh0.5Ir0.5In 5。这些实验揭示了一个反铁磁（AF）QCP在GPa的超导圆顶达到最大转变温度Tc。然而，在此之前，NQR频率ν Q在零温极限= 0.8GPa处突然增加，表明Ce的自f电子从局域特性转变为巡游特性，并伴随着费米面由小到大的变化。在Tcis优化的地方，有一个不寻常的大部分的无隙激发远低于Tc，这意味着自旋单线态，奇频配对对称性。
A fundamental problem posed from the study of correlated electron compounds, of which heavy-fermion systems are prototypes, is the need to understand the physics of states near a quantum critical point (QCP). At a QCP, magnetic order is suppressed continuously to zero temperature and unconventional superconductivity often appears. Here, we report pressure (P)-dependent115In nuclear quadrupole resonance (NQR) measurements on heavy-fermion antiferromagnet CeRh0.5Ir0.5In5. These experiments reveal an antiferromagnetic (AF) QCP atGPa where a dome of superconductivity reaches a maximum transition temperatureTc. Preceding, however, the NQR frequencyνQundergoes an abrupt increase at= 0.8 GPa in the zero-temperature limit, indicating a change from localized to itinerant character of cerium’sf-electron and associated small-to-large change in the Fermi surface. AtwhereTcis optimized, there is an unusually large fraction of gapless excitations well belowTcthat implicates spin-singlet, odd-frequency pairing symmetry.