Single-molecule quantum dot as a Kondo simulator

• Published in: Nature communications Vol. 8; no. 1; pp. 16012 - 7
• Main Authors: Hiraoka, R., Minamitani, E., Arafune, R., Tsukahara, N., Watanabe, S., Kawai, M., Takagi, N.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.06.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/544; Atomic structure; Coupling (molecular); Electrodes; Flexibility; Humanities and Social Sciences; Iron; Metal phthalocyanines; multidisciplinary; Phase transitions; Physics; Quantum dots; Scanning; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms16012

Structural flexibility of molecule-based systems is key to realizing the novel functionalities. Tuning the structure in the atomic scale enables us to manipulate the quantum state in the molecule-based system. Here we present the reversible Hamiltonian manipulation in a single-molecule quantum dot consisting of an iron phthalocyanine molecule attached to an Au electrode and a scanning tunnelling microscope tip. We precisely controlled the position of Fe 2+ ion in the molecular cage by using the tip, and tuned the Kondo coupling between the molecular spins and the Au electrode. Then, we realized the crossover between the strong-coupling Kondo regime and the weak-coupling regime governed by spin–orbit interaction in the molecule. The results open an avenue to simulate low-energy quantum many-body physics and quantum phase transition through the molecular flexibility. Tuning the structure in the atomic scale enables manipulation of the quantum state in a molecular based system. Here, Hiraoka et al . tune the Kondo coupling between molecular spins and the Au electrode by controlling the position of Fe 2+ ions in the molecular cage with a tip.