Molecular states in carbon nanotube double quantum dots
  We report electrical transport measurements through a semiconducting single-walled carbon nanotube (SWNT) with three additional top-gates. At low temperatures the system acts as a double quantum dot with large inter-dot tunnel coupling allowing for the observation of tunnel-coupled molecular states extending over the whole double-dot system. We precisely extract the tunnel coupling and identify the molecular states by the sequential-tunneling line shape of the resonances in differential conductance. 
M.R. Graeber, W.A. Coish, C. Hoffmann, M. Weiss, J. Furer, S.   Oberholzer, D. Loss, and C. Schoenenberger