Institute of Computational and Theoretical Studies
We use cryogenic scanning tunneling microscopy/spectroscopy and density-functional theory calculations to inspect the modulation of electronic states of aromatic molecules. The molecules are self-assembled on a Cu(111) surface forming molecular networks in which the molecules are in different contact configurations, including laterally-coupled to different numbers of coordination bonds and vertically-adsorbed at different heights above the substrate. We quantitatively analyze the molecular states and find that a delocalized empty molecular state is modulated by these multiple contacts in a cooperative manner: its energy is down-shifted by ~0.16 eV for each additional lateral contact and by ~0.1 eV as the vertical molecule-surface distance is reduced by 0.1 Å in the physisorption regime. We also report that in a molecule-metal-molecule system the bridging metal can mediate the electronic states of the two molecules.
Source Publication Title
Physical Review Letters
American Physical Society
© 2013 American Physical Society
Link to Publisher's Edition
Wang, Weihua, Xingqiang Shi, Shiyong Wang, Jun Liu, Michel Andre Van Hove, Pei Nian Liu, Rui-Qin Zhang, and N. Lin. "Cooperative modulation of electronic structures of aromatic molecules coupled to multiple metal contacts." Physical Review Letters 110 (2013): 046802-1-046802-5.