Sunko V, Mazzola F, Kitamura S, Khim S, Kushwaha P, Clark O J, Watson M D, Marković I, Biswas D, Pourovskii L, Kim T K, Lee T-L, Thakur P K, Rosner H, Georges A, Moessner R, Oka T, Mackenzie A P, King P D C
SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.
Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, 01187 Dresden, Germany.
Sci Adv. 2020 Feb 7;6(6):eaaz0611. doi: 10.1126/sciadv.aaz0611. eCollection 2020 Feb.
A nearly free electron metal and a Mott insulating state can be thought of as opposite ends of the spectrum of possibilities for the motion of electrons in a solid. Understanding their interaction lies at the heart of the correlated electron problem. In the magnetic oxide metal PdCrO, nearly free and Mott-localized electrons exist in alternating layers, forming natural heterostructures. Using angle-resolved photoemission spectroscopy, quantitatively supported by a strong coupling analysis, we show that the coupling between these layers leads to an "intertwined" excitation that is a convolution of the charge spectrum of the metallic layer and the spin susceptibility of the Mott layer. Our findings establish PdCrO as a model system in which to probe Kondo lattice physics and also open new routes to use the a priori nonmagnetic probe of photoemission to gain insights into the spin susceptibility of correlated electron materials.
近自由电子金属和莫特绝缘态可以被看作是固体中电子运动可能性光谱的两端。理解它们之间的相互作用是关联电子问题的核心所在。在磁性氧化物金属PdCrO中，近自由电子和莫特定域电子交替存在于不同层中，形成了天然的异质结构。通过角分辨光电子能谱，并在强耦合分析的定量支持下，我们表明这些层之间的耦合导致了一种“交织”激发，它是金属层电荷谱与莫特层自旋磁化率的卷积。我们的研究结果确立了PdCrO作为一个用于探索近藤晶格物理的模型体系，同时也开辟了新途径，利用光电子能谱这种先验的非磁性探针来深入了解关联电子材料的自旋磁化率。
