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circumcoronene_ manuscript.pdf (10.2 MB)
Ultra-high Yield On-surface Synthesis and Assembly of Circumcoronene into Chiral Electronic Kagome-honeycomb Lattice
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 14.09.2020 and posted on 15.09.2020by Mykola Telychko, Guangwu Li, Pingo Mutombo, Diego Soler-Polo, Xinnan Peng, Jie Su, Shaotang Song, Ming Joo Koh, Mark Edmonds, Pavel Jelinek, Jishan Wu, Jiong Lu
On-surface synthesis has revealed remarkable potential in the fabrication of a plethora of
elusive nanographenes with tailored structural, electronic and magnetic properties
unattainable by conventional wet-chemistry synthesis. Unfortunately, surface-assisted
synthesis often involves multiple-step cascade reactions with competing pathways, leading
to the formation of a diversity of products with limited yield, which reduces its feasibility
towards the large-scale production for future technological applications. Here, we devise a
new on-surface synthetic strategy for the ultra-high yield synthesis of a hexagonal
nanographene with six zigzag edges, namely circumcoronene on Cu(111) via surfaceassisted intramolecular dehydrogenation of the rationally-designed precursor molecule,
followed by methyl radical-radical coupling and aromatization. An elegant electrostatic
interaction between circumcoronene and Cu(111) drives their self-organization into an
extended superlattice, as revealed by bond-resolved low-temperature scanning probe
microscopy and spectroscopy measurements. Density functional theory and tight-binding
calculations reveal that unique hexagonal zigzag topology of circumcoronenes, along with
their periodic electrostatic landscape confines two-dimensional (2D) electron gas in Cu(111)
surface into chiral electronic Kagome-honeycomb lattice with two emergent electronic flat
bands. Our findings open up a new route for the high-yield fabrication of elusive
nanographenes with zigzag topologies and their novel 2D superlattices with possible nontrivial electronic properties towards their future technological applications.