Observation of Quantum Capacitance of individual single walled carbon   nanotubes
  We report a measurement on quantum capacitance of individual semiconducting and small band gap SWNTs. The observed quantum capacitance is remarkably smaller than that originating from density of states and it implies a strong electron correlation in SWNTs. 
Junfeng Dai, Jun Li, Hualing Zeng, Xiaodong Cui