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arXiv · 2112.02898

CaCu$_3$Ru$_4$O$_{12}$: a high Kondo-temperature transition metal oxide

D. Takegami·C. Y. Kuo·K. Kasebayashi·J. -G. Kim·C. F. Chang·C. E. Liu·C. N. Wu·D. Kasinathan·S. G. Altendorf·K. Hoefer·F. Meneghin·A. Marino·Y. F. Liao·K. D. Tsuei·C. T. Chen·K. -T. Ko·A. Günther·S. G. Ebbinghaus·J. W. Seo·D. H. Lee·G. Ryu·A. C. Komarek·S. Sugano·Y. Shimakawa·A. Tanaka·T. Mizokawa·J. Kuneš·L. H. Tjeng·A. Hariki
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Abstract

We present a comprehensive study of CaCu$_3$Ru$_4$O$_{12}$ using bulk sensitive hard and soft x-ray spectroscopy combined with local-density approximation (LDA) + dynamical mean-field theory (DMFT) calculations. Correlation effects on both the Cu and Ru ions can be observed. From the Cu $2p$ core level spectra we deduce the presence of magnetic Cu$^{2+}$ ions hybridized with a reservoir of itinerant electrons. The strong photon energy dependence of the valence band allows us to disentangle the Ru, Cu, and O contributions and thus to optimize the DMFT calculations. The calculated spin and charge susceptibilities show that the transition metal oxide CaCu$_3$Ru$_4$O$_{12}$ must be classified as a Kondo system and that the Kondo temperature is in the range of 500-1000 K.

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D. Takegami, C. Y. Kuo, K. Kasebayashi, J. -G. Kim, C. F. Chang, C. E. Liu, C. N. Wu, D. Kasinathan, S. G. Altendorf, K. Hoefer, F. Meneghin, A. Marino, Y. F. Liao, K. D. Tsuei, C. T. Chen, K. -T. Ko, A. Günther, S. G. Ebbinghaus, J. W. Seo, D. H. Lee, G. Ryu, A. C. Komarek, S. Sugano, Y. Shimakawa, A. Tanaka, T. Mizokawa, J. Kuneš, L. H. Tjeng, A. Hariki. 2021-12-06. CaCu$_3$Ru$_4$O$_{12}$: a high Kondo-temperature transition metal oxide. https://doi.org/10.1103/physrevx.12.011017

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