Quasiparticle interference in ZrSiS: Strongly band-selective scattering depending on impurity lattice site
Quasiparticle interference in ZrSiS: Strongly band-selective scattering depending on impurity lattice site
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DOI：
10.1103/physrevb.96.195125
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发表时间：
2017-11-13
影响因子：
3.7
通讯作者：
Lin, Minn-Tsong
中科院分区：
文献类型：
--
作者：
Butler, Christopher J.;Wu, Yu-Mi;Lin, Minn-Tsong
准粒子干涉(QPI)的扫描隧道显微镜可视化使人们能够深入了解超导、拓扑、Rashba和其他奇异电子相的k空间性质，但它们对作为散射中心的杂质的依赖很少被仔细研究。在这里，我们研究了Dirac半金属ZrSiS的真空解理(001)面的QPI。我们发现，位于Zr和S晶位上的杂质周围的干涉图样表现出很大的不同，这可以归因于主要由Zr4d导出的能带结构的不同子集的选择性散射，即m=0和+/-1组分。结果表明，散射通道的选择性需要在不同能带的轨道特征及其在Zr和S格位上各自的电荷密度分布之外进行解释。重要的是，这一结果表明，一般的散射中心允许准粒子干涉的观测不分青红皂白地和各向同性地照射到散射事件的Q空间的假设是不成立的，因此QPI观测的范围和解释可以强烈地取决于材料缺陷化学。这一发现有望推动对准粒子散射过程本身的新研究，为未来对准粒子干涉观测的解释提供信息，并最终帮助理解和设计量子电子输运性质。
Scanning tunneling microscopy visualizations of quasiparticle interference (QPI) enable powerful insights into the k-space properties of superconducting, topological, Rashba, and other exotic electronic phases, but their reliance on impurities acting as scattering centers is rarely scrutinized. Here, we investigate QPI at the vacuum-cleaved (001) surface of the Dirac semimetal ZrSiS. We find that interference patterns around impurities located on the Zr and S lattice sites appear very different, and can be ascribed to selective scattering of different subsets of the predominantly Zr 4d-derived band structure, namely, the m = 0 and +/- 1 components. We show that the selectivity of scattering channels requires an explanation beyond the different bands' orbital characteristics and their respective charge density distributions over Zr and S lattice sites. Importantly, this result shows that the usual assumption of generic scattering centers allowing observations of quasiparticle interference to shed light indiscriminately and isotropically upon the q space of scattering events does not hold, and that the scope and interpretation of QPI observations can therefore be be strongly contingent on the material defect chemistry. This finding promises to spur new investigations into the quasiparticle scattering process itself, to inform future interpretations of quasiparticle interference observations, and ultimately to aid the understanding and engineering of quantum electronic transport properties.