Scientists at Lancaster University and the University of Oxford have made a nano-electronic circuit which vibrates without ant external power. They just used a small suspended wire that looks like a vibrating guitar string and shows that a simple nano-device can generate motion directly from an electrical current.
Scientists created a device using a wire of carbon nanotube of diameter 3 nanometres- 100,000 times thinner than a guitar string. They mounted it on metal supports at each end and then cooled it to a temperature of 0.02 degrees above absolute zero. The central part of the wire was free to vibrate, which the scientists could identify by going passing through it and estimating a change in electrical resistance.
When a guitar string is plucked, the string vibrates and creates sound. The same thing happened here: the wire vibrates when it is forced into motion by an oscillating voltage.
Scientists were surprised when they repeated the experiment without the forcing voltage. They observed that the wire oscillated of its own accord under the right conditions.
Lead researcher Dr. Edward Laird of Lancaster University said, “It took us a while to work out what was causing the vibrations, but we eventually understood. In such a tiny device, it is important that an electrical current consists of individual electrons.”
“The electrons hop one by one onto the wire, each giving it a small push. Usually, these pushes are random, but we realized that when you control the parameters just right, they will synchronize and generate an oscillation.”
“The nanotube is far thinner than a guitar string, so it oscillates at a much higher frequency—well into the ultrasound range so no human would be able to hear it. However, we can still assign it a note. Its frequency is 231 million hertz, which means it’s an A string, pitched 21 octaves above standard tuning.”
The research has been published in Nature Physics.