Gap plasmonics of silver nanocube dimers
  We theoretically investigate gap plasmons for two silver nanocubes coupled through a molecular tunnel junction. In absence of tunneling, the red-shift of the bonding mode saturates with decreasing gap distance. Tunneling at small gap distances leads to a damping and slight blue-shift of the bonding mode, but no low-energy charge transfer plasmon mode appears in the spectra. This finding is in stark contrast to recent work of Tan et al. [Science 343, 1496 (2014)]. 
Dario Knebl, Anton H\"orl, Andreas Tr\"ugler, Johannes Kern, Joachim   R. Krenn, Peter Puschnig, Ulrich Hohenester
cond-mat.mes-hall