Origin of high-energy charge excitations observed by resonant inelastic X-ray scattering in cuprate superconductors
Origin of high-energy charge excitations observed by resonant inelastic X-ray scattering in cuprate superconductors
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DOI：
10.1038/s42005-018-0099-z
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发表时间：
2019-01
影响因子：
5.5
通讯作者：
A. Greco;H. Yamase;M. Bejas
中科院分区：
文献类型：
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作者：
A. Greco;H. Yamase;M. Bejas
X射线散射技术的最新发展揭示了高TcCu3+超导体的电荷激发谱。虽然高能电荷激发谱中色散信号的存在在电子掺杂铜酸盐中得到了很好的接受，但它的解释和普适性是有争议的。由于电荷起伏在铜酸盐超导体中普遍存在，因此对其起源的理解是一个关键问题。在这里，我们使用了长程库仑相互作用的分层−J模型，并表明在面内动量为(0，0)处具有间隙的类声学等离子体激元模式捕捉到了高能电荷激发的主要特征。因此，高能电荷激发应该是铜酸盐超导体的普遍特征，在空穴掺杂的铜酸盐中也是如此。铜酸盐中的类声学等离子体还没有在实验中被识别出来。我们提出了几个实验测试来区分对高能电荷激发的不同解释。
The recent development of x-ray scattering techniques revealed the charge-excitation spectrum in high-Tccuprate superconductors. While the presence of a dispersive signal in the high-energy charge-excitation spectrum is well accepted in the electron-doped cuprates, its interpretation and universality are controversial. Since charge fluctuations are observed ubiquitously in cuprate superconductors, the understanding of its origin is a pivotal issue. Here, we employ the layeredt−Jmodel with the long-range Coulomb interaction and show that an acoustic-like plasmon mode with a gap at in-plane momentum (0, 0) captures the major features of the high-energy charge excitations. The high-energy charge excitations, therefore, should be a universal feature in cuprate superconductors and are expected also in the hole-doped cuprates. Acoustic-like plasmons in cuprates have not been recognized yet in experiments. We propose several experimental tests to distinguish different interpretations of the high-energy charge excitations.