Spectroscopic Fingerprint of Phase-Incoherent Superconductivity in the Underdoped Bi2Sr2CaCu2O8+δ
Spectroscopic Fingerprint of Phase-Incoherent Superconductivity in the Underdoped Bi2Sr2CaCu2O8+δ
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DOI：
10.1126/science.1176369
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发表时间：
2009-08-28
期刊：
影响因子：
56.9
通讯作者：
Davis, J. C.
中科院分区：
文献类型：
--
作者：
Lee, Jhinhwan;Fujita, K.;Davis, J. C.
对于铜酸盐“赝能隙”态存在的一个可能的解释是，它是一种没有量子相刚性的d波超导体。输运和热力学研究提供了令人信服的证据来支持这一提议，但对其进行的光谱探索却很少。 d 波超导性的一个光谱特征是色散 Bogoliubov 准粒子干涉调制的粒子孔对称“八位组”。在这里，我们报告了这个八位组从低温到良好的欠掺杂赝能隙状态的演变。在超导体的临界温度 T-c 下，八位组现象没有发生明显的变化，并且它至少可以维持到类似于 1.5 T-c 的温度 T。在这种赝能隙区域中，我们观察到了理论上预测的相位非相干 d 波超导体中准粒子干涉的详细现象学。因此，我们的结果不仅提供了光谱证据来确认和扩展输运和热力学研究，而且还为光谱探索相波动率、其对费米弧的影响以及抑制欠掺杂铜酸盐中超导性的相波动的根本来源开辟了道路。
A possible explanation for the existence of the cuprate "pseudogap" state is that it is a d-wave superconductor without quantum phase rigidity. Transport and thermodynamic studies provide compelling evidence that supports this proposal, but few spectroscopic explorations of it have been made. One spectroscopic signature of d-wave superconductivity is the particle-hole symmetric " octet" of dispersive Bogoliubov quasiparticle interference modulations. Here we report on this octet's evolution from low temperatures to well into the underdoped pseudogap regime. No pronounced changes occur in the octet phenomenology at the superconductor's critical temperature T-c, and it survives up to at least temperature T similar to 1.5 T-c. In this pseudogap regime, we observe the detailed phenomenology that was theoretically predicted for quasiparticle interference in a phase-incoherent d-wave superconductor. Thus, our results not only provide spectroscopic evidence to confirm and extend the transport and thermodynamics studies, but they also open the way for spectroscopic explorations of phase fluctuation rates, their effects on the Fermi arc, and the fundamental source of the phase fluctuations that suppress superconductivity in underdoped cuprates.