NCAFM2023 Programme Booklet

Peng Xinnan 1 , Marco Aurelio Lozano 2 , Wang Lulu 1 , Su Jie 1 , Thomas Tuloup 3 , Diego Soler Polo 2 , Gong Jiangbin 3* , Wong Ming Wah 1* , Pavel Jel ί nek 2,4* , Lu Jiong 1,5* QUENCH OF PEIERLS INSTABILITY IN A 1D TOPOLOGICAL POLYACETYLENE

1 Department of Chemistry, National University of Singapore, 117543 Singapore 2 Institute of Physics, Czech Academy of Science, 16200 Czech Republic 3 Department of Physics, National University of Singapore, 117551 Singapore

4 Regional Centre of Advanced Technologies and Materials, Palacký University, 78371 Czech Republic 5 Centre for Advanced 2D Materials (CA2DM), National University of Singapore, 117543 Singapore Email: chmluj@nus.edu.sg

Trans-polyacetylene, with a topology of single/double bond alternation, plays as a model system that can host many exotic quantum properties like topological transition and in-gap soliton state. Here, we show an approach to prepare atomically precise odd-number trans-polyacetylene chains with the presence of a soliton state. We further probed a unique quench of bond length alternation or Peierls instability in this structure by NC-AFM imaging. We further demonstrated the controllable bond length alternation via tip manipulation. Our studies open up a new avenue to fabricate organic quantum nanostructures with atomic precision to engineer desired topological quantum phases.

Fig. (a) Chemical structures of the different products after tip manipulation. (b, d, f) Corresponding constant-height NC-AFM images of Product 1-3, respectively. (c, e, g) Corresponding zoom-in constant-height NC-AFM images of the center polyacetylene chain in Product 1-3, respectively. (h) DFT calculated bond lengths of the center polyacetylene chains in Product 1-3. The scale bars in (b, d, f) and (c, e, g) are 4.8 and 0.6 Å, respectively.

References [1] Heeger, A. J., Kivelson, S., Schriefer, J. R. & Su, W. P., Rev. Mod. Phys., 1988, 60 , 781–850. [2] Peierls, R. E., Quantum theory of solids. Oxford University Press, 1955.

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