Engineers and material scientists have long been trying to find out an effective way to control heat energy at the atomic level so it could be recycled and made more efficient.
Now, researchers from the University of Minnesota (UMN) have captured groundbreaking observations that show how heat moves through material at the nanoscale level while moving at the speed of sound.
This discovery could help experts produce more powerful materials for electronics and alternative energy, as well as reduce the use of fossil fuels.
How Heat Moves Through Material
Controlling heat at the nanolevel is difficult because of the extremely rapid speed and the tiny size involved in the research.
To accomplish this amazing feat, UMN scientists used a state-of-the-art ultrafast electron microscope (UEM) and succeeded in watching heat energy move through the material.
With the help of the FEI Tecnai Femto UEM, researchers captured the slow-motion videos of the material. They also used a brief laser pulse to trigger electrons and very quickly heat crystalline semiconducting materials of germanium and tungsten diselenide.
The slow-motion footage was slowed by more than a billion times than normal speed. The result? Researchers saw heat energy waves moving through crystals.
Chemical Engineering Assistant Professor David Flannigan, the lead researcher of the study, said as soon as they saw the waves, they knew it was an extremely exciting breakthrough.
What's more, the heat energy movement was akin to the ripples on a pond after you drop a pebble on the water, scientists said. Heat energy waves moved at about six nanometers per picosecond.
"Watching this process happen at the nanoscale is a dream come true," added Flannigan.
Implications Of The Discovery
Heat energy is a major factor in the design of public infrastructure and electronic devices, as well as a huge form of waste energy. UMN researchers say 70 percent of gas energy is wasted as heat in vehicles.
Plotting the oscillations of energy, known as phonons, at the nanoscale is crucial in creating a better understanding of the fundamentals of thermal energy motion.
By understanding this oscillation, scientists believe there is a better chance of controlling heat energy, collecting it and guiding it.
The findings of the study are featured in the journal Nature Communications. The research is supported by the National Science Foundation.
Watch the video below.
