Basins of attraction of a nonlinear nanomechanical resonator.

We present an experiment that systematically probes the basins of attraction of two fixed points of a nonlinear nanomechanical resonator and maps them out with high resolution. We observe a separatrix which progressively alters shape for varying drive strength and changes the relative areas of the two basins of attraction. The observed separatrix is blurred due to ambient fluctuations, including residual noise in the drive system, which cause uncertainty in the preparation of an initial state close to the separatrix. We find a good agreement between the experimentally mapped and theoretically calculated basins of attraction.

Carbon nanotube linear bearing nanoswitches.

We exploit the remarkable low-friction bearing capabilities of multiwalled carbon nanotubes (MWNTs) to realize nanoelectromechanical switches. Our switches consist of two open-ended MWNT segments separated by a nanometer-scale gap. Switching occurs through electrostatically actuated sliding of the inner nanotube shells to close the gap, producing a conducting ON state. For double-walled nanotubes in particular, a gate voltage can restore the insulating OFF state. Acting as a nonvolatile memory element capable of several switching cycles, our devices are straightforward to implement, self-aligned, and do not require complex fabrication or geometries, allowing for convenient scalability.

Ballistic phonon thermal transport in multiwalled carbon nanotubes.

We report electrical transport experiments, using the phenomenon of electrical breakdown to perform thermometry, that probe the thermal properties of individual multiwalled carbon nanotubes. Our results show that nanotubes can readily conduct heat by ballistic phonon propagation. We determine the thermal conductance quantum, the ultimate limit to thermal conductance for a single phonon channel, and find good agreement with theoretical calculations. Moreover, our results suggest a breakdown mechanism of thermally activated C-C bond breaking coupled with the electrical stress of carrying approximately 10(12) A/m2. We also demonstrate a current-driven self-heating technique to improve the conductance of nanotube devices dramatically.

Correlated tunneling in intramolecular carbon nanotube quantum dots.

We investigate correlated electronic transport in single-walled carbon nanotubes with two intramolecular tunneling barriers. We suggest that below a characteristic temperature the long-range nature of the Coulomb interaction becomes crucial to determine the temperature dependence of the maximum G(max) of the conductance peak. Correlated sequential tunneling dominates transport yielding the power law G(max) proportional, variant T(alpha(end-end)-1), typical for tunneling between the ends of two Luttinger liquids. Our predictions are in agreement with recent measurements.

Carbon nanotube single-electron transistors at room temperature.

Room-temperature single-electron transistors are realized within individual metallic single-wall carbon nanotube molecules. The devices feature a short (down to approximately 20 nanometers) nanotube section that is created by inducing local barriers into the tube with an atomic force microscope. Coulomb charging is observed at room temperature, with an addition energy of 120 millielectron volts, which substantially exceeds the thermal energy. At low temperatures, we resolve the quantum energy levels corresponding to the small island. We observe unconventional power-law dependencies in the measured transport properties for which we suggest a resonant tunneling Luttinger-liquid mechanism.