Yang, Yang and Gantenbein, Markus and Alqorashi, Afaf and Wei, Junying and Sangtarash, Sara and Hu, Duan and Sadeghi, Hatef and Zhang, Rui and Pi, Jiuchan and Chen, Lichuan and Huang, Xiaoyan and Li, Ruihao and Liu, Junyang and Shi, Jia and Hong, Wenjing and Lambert, Colin J. and Bryce, Martin R. (2018) Heteroatom-Induced Molecular Asymmetry Tunes Quantum Interference in Charge Transport through Single-Molecule Junctions. The Journal of Physical Chemistry C, 122 (26). pp. 14965-14970. ISSN 1932-7447
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Abstract
We studied the interplay between quantum interference (QI) and molecular asymmetry in charge transport through a single molecule. Eight compounds with five-membered core rings were synthesized, and their single-molecule conductances were characterized using the mechanically controllable break junction technique. It is found that the symmetric molecules are more conductive than their asymmetric isomers and that there is no statistically significant dependence on the aromaticity of the core. In contrast, we find experimental evidence of destructive QI in five-membered rings, which can be tuned by implanting different heteroatoms into the core ring. Our findings are rationalized by the presence of antiresonance features in the transmission curves calculated using nonequilibrium Green’s functions. This novel mechanism for modulating QI effects in charge transport via tuning of molecular asymmetry will lead to promising applications in the design of single-molecule devices.