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arXiv 0903.1674cond-mat.supr-concond-mat.str-el
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用涡旋准粒子散射探测高温铜氧化物的相干因子

Coherence factors in a high-Tc cuprate probed by quasi-particle scattering off vortices

T. Hanaguri, Y. Kohsaka, M. Ono, M. Maltseva, P. Coleman, I. Yamada, M. Azuma, M. Takano, K. Ohishi, H. Takagi

摘要:

相干因子是超导性作为对凝聚现象的标志。当电子成对时,准粒子对不同类型的散射势发展出一种敏锐的敏感性,这种敏感性通过散射振幅中出现的相干因子来描述。虽然相干因子的影响在各向同性超导体中得到了很好的证实,但它们在各向异性超导体中更难检测到,例如高Tc铜酸盐。在这里,我们展示了一种新的方法,突出了动量依赖的相干因子在Ca 2-xNaxCuO 2Cl 2。使用傅里叶变换扫描隧道光谱检测准粒子干涉效应,我们的实验揭示了准粒子散射的磁场依赖性是敏感的各向异性间隙的符号。这一结果可以理解的d-波相干因子,它揭示了准粒子散射中心的旋涡的作用。我们还表明,一个磁场引起的间隙节点周围的一个扩大的无间隙区域。

英文摘要:

Coherence factors are a hallmark of superconductivity as a pair-condensation phenomenon. When electrons pair, quasi-particles develop an acute sensitivity to different types of scattering potential, described by the appearance of coherence factors in the scattering amplitudes. While the effects of coherence factors are well established in isotropic superconductors, they are much harder to detect in their anisotropic counterparts, such as high-Tc cuprates. Here we demonstrate a new approach which highlights the momentum-dependent coherence factors in Ca2-xNaxCuO2Cl2. Using Fourier-transform scanning tunnelling spectroscopy to detect quasi-particle interference effects, our experiments reveal a magnetic-field dependence in quasi-particle scattering which is sensitive to the sign of the anisotropic gap. This result can be understood in terms of d-wave coherence factors and it exposes the role of vortices as quasi-particle scattering centers. We also show that a magnetic field gives rise to an enlarged gapless region around the gap nodes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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