NCAFM2023 Programme Booklet

Monday 1200-1220

REGULATING REACTION PATHWAYS IN COORDINATED CHAINS BY THE DIRECTION OF MECHANICAL FORCES

Xin Li, Zhen Xu, Jie Li, Yajie Zhang, Yongfeng Wang*

School of Electronics, Peking University, 100871 China Email: yongfengwang@pku.edu.cn

Manipulation at atomic and molecular scales has been achieved widely with a scanning tunneling microscope (STM) or atom force microscope (AFM), which contributes to the development of functional nanoscale devices. The manipulation can be achieved in various ways such as the electrical field, the stimulation of the tunneling electrons, or the interaction forces between tip and sample. In our previous work, we have achieved the manipulation of the spin state in the coordinated chains, where the Ni atoms coordinated by deprotonated tetrahydroxybenzene linkers on Au(111) are at a low-spin (S = 0) or a high-spin (S = 1) state alternately along the chains. Here, we use Au and C60 tips to realize reversible manipulation of the above-mentioned Ni atoms. Combining the STM, AFM, and density functional theory (DFT) calculations, we find that the Au (C60) tip could pull (push) the Ni atoms, and induce the transition from high-spin (low-spin) to low-spin (high-spin) state by attractive (repulsive) force. During the manipulation, the collective switching of multiple Ni atoms can be restricted in a single chain, suggesting that the manipulation by mechanical force is more localized than the stimulation of electrons. These findings provide more possibilities for the application of mechanochemistry in multifunctional spintronics.

Fig. Schematics of an Au tip pulling the Ni atom from high-spin state into low-spin state by attractive force (left), and a C60 tip pushing the Ni atom from low-spin state into high-spin state by repulsive force (right). Color code: gray, C; white, H; red, O; gray-blue, Ni; yellow, Au.

References [1] Jing Liu, Yifan Gao, Tong Wang, Qiang Xue, Muqing Hua, Yongfeng Wang, Li Huang, and Nian Lin ACS Nano 2020 14, 9

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