Quasiparticle interference and strong electron–mode coupling in the quasi-one-dimensional bands of Sr2RuO4
Quasiparticle interference and strong electron–mode coupling in the quasi-one-dimensional bands of Sr2RuO4
复制标题
DOI：
10.1038/nphys4107
复制
发表时间：
2017-01
期刊：
影响因子：
19.6
通讯作者：
Zhenyu Wang;D. Walkup;P. Derry;Thomas Scaffidi;M. Rak;S. Vig;A. Kogar;I. Zeljkovic;A. Husain-
中科院分区：
文献类型：
--
作者：
Zhenyu Wang;D. Walkup;P. Derry;Thomas Scaffidi;M. Rak;S. Vig;A. Kogar;I. Zeljkovic;A. Husain-
单层的单齿酸盐Sr 2 RuO 4是一个潜在的自旋三重态超导体的序参数，可能会打破时间反演不变性和主机半量子化的涡旋与马约拉纳零模式。虽然超导态的实际性质仍然是一个有争议的问题，但人们认为它是从传统费米液体很好地描述的金属态凝结而成的。在这项工作中，我们使用相结合的傅里叶变换扫描隧道光谱（FT-STS）和动量分辨电子能量损失谱（M-EELS）探测在正常状态下的Sr 2 RuO 4的相互作用的影响。我们的高分辨率FT-STS数据显示了具有明显准一维（1D）特征的β带特征。带色散揭示了令人惊讶的强相互作用的影响，显着renormalize费米速度，这表明Sr 2 RuO 4的正常状态是一个“相关金属”的相关性加强准一维性质的频带。此外，扭结的能量约为10 meV，38 meV和70 meV的观察。通过比较STM和M-EELS数据，我们表明，这两个更高的能量的功能产生与集体模式的耦合。强关联效应和准一维带中的扭结现象为理解超导态提供了重要信息。
The single-layered ruthenate Sr2RuO4is presented as a potential spin-triplet superconductor with an order parameter that may break time-reversal invariance and host half-quantized vortices with Majorana zero modes. Although the actual nature of the superconducting state is still a matter of controversy, it is believed to condense from a metallic state that is well described by a conventional Fermi liquid. In this work we use a combination of Fourier transform scanning tunnelling spectroscopy (FT-STS) and momentum-resolved electron energy loss spectroscopy (M-EELS) to probe interaction effects in the normal state of Sr2RuO4. Our high-resolution FT-STS data show signatures of the β-band with a distinctly quasi-one-dimensional (1D) character. The band dispersion reveals surprisingly strong interaction effects that dramatically renormalize the Fermi velocity, suggesting that the normal state of Sr2RuO4is that of a ‘correlated metal’ where correlations are strengthened by the quasi-1D nature of the bands. In addition, kinks at energies of approximately 10 meV, 38 meV and 70 meV are observed. By comparing STM and M-EELS data we show that the two higher energy features arise from coupling with collective modes. The strong correlation effects and the kinks in the quasi-1D bands could provide important information for understanding the superconducting state.