Dehydrogenation Induced Formation of Chiral Core-Shell Arrays of Melamine on Ag(111)
Hexu Zhang1,2, Yuanhao Lyu1,2, Wenqi Hu1,2, Lan Chen1,2,3, Yi-Qi Zhang1,3*, and Kehui Wu1,2,3*
1Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China 2School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China 3Songshan Lake Materials Laboratory, Dongguan 523808, China
Abstract：The structural evolution of supramolecular phases of melamine on Ag(111) surface as a function of annealing temperature is investigated by employing low-temperature scanning tunneling microscopy/spectroscopy (LT-STM/STS). It is found that partial deprotonation of the melamine molecules leads to formation of distinct types of ordered supramolecular arrangements. Apart from two previously reported phases ($\alpha$ and $\beta$), a new phase comprising arrays of close-packed hexagonal core-shell-type clusters is identified for the first time. Based on high-resolution STM images as well as structural modeling, we show that the new phase presents a two-level hierarchical order and chirality is expressed at both levels. Using STS characterization, we further reveal that the chiral arrangement of the clusters confines surface electrons into a honeycomb pathway with handedness, which could give rise to novel interfacial electronic properties such as Dirac fermions as well as flat band.
Xu W, Dong M, Gersen H, Rauls E, Vázquez-Campos S, Crego-Calama M, Reinhoudt D N, Stensgaard I, Lægsgaard E, Linderoth T R, and Besenbacher F 2007 Small3 854
Wieghold S, Li J, Simon P, Krause M, Avlasevich Y, Li C, Garrido J A, Heiz U, Samorì P, Müllen K, Esch F, Barth J V, and Palma C A 2016 Nat. Commun.7 10700
[36]
Thomas A, Fischer A, Goettmann F, Antonietti M, Müller J O, Schlögl R, and Carlsson J M 2008 J. Mater. Chem.18 4893
Yue S, Zhou H, Geng D, Sun Z, Arita M, Shimada K, Cheng P, Chen L, Meng S, Wu K, and Feng B 2020 Phys. Rev. B102 201401
[70]
Telychko M, Li G, Mutombo P, Soler-Polo D, Peng X, Su J, Song S, Koh M J, Edmonds M, Jelínek P, Wu J, and Lu J 2021 Sci. Adv.7 eabf0269
[71]
Nowakowska S, Wäckerlin A, Piquero-Zulaica I, Nowakowski J, Kawai S, Wäckerlin C, Matena M, Nijs T, Fatayer S, Popova O, Ahsan A, Mousavi S F, Ivas T, Meyer E, Stöhr M, Ortega J E, Björk J, Gade L H, Lobo-Checa J, and Jung T A 2016 Small12 3757
[72]
Hu W, Kher-Elden M A, Zhang H, Cheng P, Chen L, Piquero-Zulaica I, Abd E F Z M, Barth J V, Wu K, and Zhang Y Q 2022 Nanoscale14 7039
2022, Vol. 39 
