Modeling electrostatically induced collapse transitions in carbon nanotubes

Molecular dynamics simulations demonstrate how a mechanically bistable single-walled carbon nanotube can act as a variable-shaped capacitor. If the voltage is tuned so that collapsed and inflated states are degenerate, the tube's susceptibility to diverse external stimuli-temperature, voltage, trapped atoms-diverges following a universal curve, yielding an exceptionally sensitive sensor or actuator. The boundary between collapsed and inflated states can shift hundreds of angstroms in response to a single gas atom inside the tube. Several potential nanoelectromechanical devices could be based on this electrically tuned crossover between near-degenerate collapsed and inflated configurations.