Nanoelectronic device could advance sound-based lasers
A quantum nanoelectronic device that generates phonons at extremely low temperatures could have applications in sensors, biological materials and medical systems.
Researchers at McGill University, Canada, have developed the device, which works by passing an electrical current through a 2D crystalline layer, trapping electrons within a channel only a few atoms thick. When pushed through the channel hard enough, the electrons release energy as bursts of phonons in predictable and tuneable patterns.
The experiments were carried out at temperatures between around 10mK and 3.9K, where electron behaviour becomes more predictable and quantum effects can be observed.
‘At absolute zero temperatures – that is, the world of quantum physics – no sound is created unless electrons travel collectively at the speed of sound or above,’ says Michael Hilke, Associate Professor of Physics at McGill. ‘Earlier work had observed related effects as electron speeds approached the sound barrier. Our study goes further by pushing the system well beyond that point and showing that existing theories need to be reassessed by considering that electrons can be very hot even if the host crystal is close to absolute zero temperature.’
The research could support the development of phonon lasers that generate coherent sound waves rather than light. The team now plans to explore other materials, including graphene, to increase device speed.
