Observation of Kondo cloud-coupling in a mirror-symmetric carbon nanotube array-molybdenum structure.

Wei, Zheng; Peng, Zhisheng; Wan, Yu-Hao; Wang, Zhongpu; Han, Ziyi; Zhao, Xiaoxu; Shi, Enzheng; Li, Yong Jun et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Magnetic impurities in a non-magnetic metal are screened by conduction electrons, forming a spin cloud known as a Kondo cloud. Experimental detection of this Kondo screening cloud in dilute magnetic alloys remains challenging. Here we show evidence of Kondo clouds and their coupling in devices composed of mirror-symmetric carbon nanotube arrays separated by a molybdenum strip. The Kondo effect in these devices depends sensitively on the width of the molybdenum strip. For widths of 0.3-1.2 micrometers and 1.5-3.0 micrometers, the Kondo temperature forms two plateaus at about 107.8 kelvin and 15.8 kelvin, respectively. These results are explained by the formation of Kondo clouds and by intra-edge and inter-edge coupling within molybdenum. Calculations based on a two-spin model reproduce the two plateaus and their crossover. These findings may open opportunities for applications in spintronics and quantum computing.