Abstract-Quantum Plasmon Resonances Controlled by Molecular Tunnel Junctions

1. Shu Fen Tan1, 
2. Lin Wu2, 
3. Joel K.W. Yang3,4, 
4. Ping Bai*,2, 
5. Michel Bosman*,3, 
6. Christian A. Nijhuis*,1,3,5,6
7. 1. http://www.sciencemag.org/content/343/6178/1496.abstract

-Author Affiliations

1. ¹Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
2. ²Institute of High Performance Computing, A*STAR (Agency for Science, Technology and Research), 1 Fusionopolis Way, 16-16 Connexis North, Singapore 138632, Singapore.
3. ³Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore 117602, Singapore.
4. ⁴Singapore University of Technology and Design, 20 Dover Drive, Singapore 138682, Singapore.
5. ⁵Graphene Research Center, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
6. ⁶Solar Energy Research Institute of Singapore (SERIS), National University of Singapore, Singapore 117574, Singapore.

1. ↵*Corresponding author. E-mail: baiping@ihpc.a-star.edu.sg (P.B.), michel.bosman@gmail.com (M.B.),christian.nijhuis@nus.edu.sg (C.A.N.)

Quantum tunneling between two plasmonic resonators links nonlinear quantum optics with terahertz nanoelectronics. We describe the direct observation of and control over quantum plasmon resonances at length scales in the range 0.4 to 1.3 nanometers across molecular tunnel junctions made of two plasmonic resonators bridged by self-assembled monolayers (SAMs). The tunnel barrier width and height are controlled by the properties of the molecules. Using electron energy-loss spectroscopy, we directly observe a plasmon mode, the tunneling charge transfer plasmon, whose frequency (ranging from 140 to 245 terahertz) is dependent on the molecules bridging the gaps.