Phase-resolved Higgs response in superconducting cuprates
Phase-resolved Higgs response in superconducting cuprates
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DOI：
10.1038/s41467-020-15613-1
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发表时间：
2020-04-14
影响因子：
16.6
通讯作者：
Kaiser, Stefan
中科院分区：
文献类型：
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作者：
Chu, Hao;Kim, Min-Jae;Kaiser, Stefan
在高能物理学中，希格斯场耦合到规范玻色子和费米子，并为它们的元激发提供质量。在实验上，这种耦合可以从希格斯玻色子的衰变产物中推断出来，即，希格斯场的标量（振幅）激发。在超导体中，库珀对与希格斯场非常相似。库珀对与其他自由度之间的相互作用为振幅模提供了耗散通道，这可能揭示微观配对机制的重要信息。为此，我们研究了Higgs（振幅）模式的几个铜氧化物薄膜使用相位分辨太赫兹三次谐波产生（THG）。除了重阻尼的希格斯模式本身，我们观察到一个普遍的跳跃阶段的驱动希格斯振荡，以及一个非零的THG以上的T-C。这些发现表明，耦合的希格斯模式，其他集体模式和潜在的非零配对振幅以上的Tc。库珀对和其他集体激发之间的相互作用可能揭示关于配对机制的重要信息。在这里，作者观察到在铜氧化物薄膜中驱动希格斯振荡的相位中的普遍跳跃，表明存在耦合集体模式，以及在高温下的非零希格斯响应，这表明在Tc以上存在潜在的非零配对振幅。
In high-energy physics, the Higgs field couples to gauge bosons and fermions and gives mass to their elementary excitations. Experimentally, such couplings can be inferred from the decay product of the Higgs boson, i.e., the scalar (amplitude) excitation of the Higgs field. In superconductors, Cooper pairs bear a close analogy to the Higgs field. Interaction between the Cooper pairs and other degrees of freedom provides dissipation channels for the amplitude mode, which may reveal important information about the microscopic pairing mechanism. To this end, we investigate the Higgs (amplitude) mode of several cuprate thin films using phase-resolved terahertz third harmonic generation (THG). In addition to the heavily damped Higgs mode itself, we observe a universal jump in the phase of the driven Higgs oscillation as well as a non-vanishing THG above T-c. These findings indicate coupling of the Higgs mode to other collective modes and potentially a nonzero pairing amplitude above T-c. Interaction between Cooper pairs and other collective excitations may reveal important information about the pairing mechanism. Here, the authors observe a universal jump in the phase of the driven Higgs oscillations in cuprate thin films, indicating the presence of a coupled collective mode, as well as a nonvanishing Higgs-like response at high temperatures, suggesting a potential nonzero pairing amplitude above Tc.