Driving carbon nanotube to rotate by diamond wedges at room temperature

A rotary nanomotor made of carbon nanostructures is introduced here. Through a rotationally symmetrical layout of diamond wedges (or needles) outside of a carbon nanotube and with the [100] direction of diamond along the tube's axial direction, the wedge needle tips can drive the nanotube to rotate at gigahertz frequency at room temperature. During thermal vibration, some of the atoms in the nanotube collide with the needle tips. The tips provide the atoms with continuous repulsion during collision. The tangential component of the repulsion force produces a moment onto the nanotube about the tube axis. Consequently, the nanotube is driven to rotate by the moment. The rotor reaches stable rotation when the concentric outer tubes provide equivalent resistance against the repulsion from needle tips. Molecular dynamics simulation results indicate that the stability of the needle tips influences the rotational frequency of the rotor. Potential fabrication of such a nanomotor is illustrated with consideration of miniaturization. The rotary motor can act as an engine in a nanomachine.