Observation of Franck-Condon Blockade in Single Molecules Gated by Local Electric Field
ORAL
Abstract
Electron transport through single molecules is greatly influenced by a discrete spectrum of vibrational modes in strong electron-vibron coupling regime. Theory predicts a current suppression at low biases known as Franck-Condon blockade. However, how Franck-Condon blockade emerges in in a real orbital-gated single molecule transistor is still elusive. In this study, by using a low-temperature scanning tunneling microscope, we report the real-space observation of Franck-Condon blockade in single molecules adsorbed on metal surfaces. The frontier molecular orbitals and charge state of the molecules are shown to be electrostatically gated by variation in the underlying surface potential and local chemical environment, allowing the observation of coulomb blockade as well as the Franck-Condon blockade. Moreover, strongly enhanced inelastic cotunneling is evidenced to dominate the electron transport in the Franck-Condon blockade regime, leading to unprecedented high-contrast single molecule vibrational spectroscopy and microscopy.
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Authors
Aidi Zhao
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Chunsheng Zhou
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Weiyi Wang
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Guangjun Tian
Division of Theoretical Chemistry \& Biology, KTH Royal Institute of Technology
Huan Shan
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Shulai Lei
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Yingbo Zhao
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Yi Luo
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Qunxiang Li
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
Bing Wang
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
J.G. Hou
Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China
