Self-detecting gate-tunable nanotube paddle resonators
  We have fabricated suspended metal paddle resonators with carbon nanotubes functioning as self-detecting torsional springs. We observe gate-tunable resonances, that either tune to higher or to lower frequencies when increasing the dc voltage on the back-gate. We attribute the former modes to flexural vibrations of the paddle resonator, while the latter ones are identified as torsional vibrations. Compared to top-down silicon fabricated paddle resonators, nanotube springs have smaller torsional spring constants and provide a larger frequency tunability. 
B. Witkamp, M. Poot, H. Pathangi, A. K. Huettel and H. S. J. van der   Zant