Quantum phase transitions and the role of impurity-substrate hybridization in Yu-Shiba-Rusinov states
Quantum phase transitions and the role of impurity-substrate hybridization in Yu-Shiba-Rusinov states
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DOI：
10.1038/s42005-020-00469-0
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发表时间：
2020-11-04
影响因子：
5.5
通讯作者：
Ast, Christian R.
中科院分区：
文献类型：
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作者：
Huang, Haonan;Drost, Robert;Ast, Christian R.
超导体内部磁性杂质的自旋相关散射在超导带隙中产生YSR态。它们可以用很大程度上等效的Kondo或安德森杂质模型来模拟。杂质的磁性和磁性与衬底耦合的关系仍有争议。在这里，我们使用扫描隧道显微镜，使一个YSR态的能量和杂质基板杂化之间的定量联系。我们证实了杂质衬底耦合作为一个关键的能量尺度的表面衍生的YSR状态使用安德森杂质模型。通过结合YSR态谱和额外的电导测量的实验数据，我们可以确定系统位于量子相变的哪一侧。因此，我们提供了一个关键的一步，更定量地了解杂质衬底耦合的关键作用，利用安德森模型。存在于超导能隙中的Yu-Shiba-Rusinov态的物理学是一个热门的研究领域，与马约拉纳费米子等奇异现象有关。在这里，作者使用扫描隧道显微镜来研究杂质对超导表面的影响以及杂质-衬底杂化对这种状态的作用。
Spin-dependent scattering from magnetic impurities inside a superconductor gives rise to Yu-Shiba-Rusinov (YSR) states within the superconducting gap. They can be modeled by the largely equivalent Kondo or Anderson impurity models. The role of the magnetic and nonmagnetic properties of the impurity in relation to the coupling to the substrate is still under debate. Here, we use a scanning tunneling microscope to make a quantitative connection between the energy of a YSR state and the impurity-substrate hybridization. We corroborate the impurity substrate coupling as a key energy scale for surface derived YSR states using the Anderson impurity model. By combining experimental data from YSR state spectra and additional conductance measurements, we can determine on which side of the quantum phase transition the system resides. We thus provide a crucial step towards a more quantitative understanding of the crucial role of impurity substrate coupling utilizing the Anderson model. The physics of Yu-Shiba-Rusinov states which exist in the superconducting gap are a topical area of research and linked to exotic phenomena such as Majorana fermions. Here, the authors use scanning tunnelling microscopy to investigate the influence of impurities on a superconducting surface and the role impurity-substrate hybridisation has on such states.