optical phonons tagged posts

You may not be able to hear it, but all solid materials make a sound. In fact, atoms—bound in lattices of chemical bonds—are never silent nor still: Under the placid surface of each and every object in our surroundings, a low hum hovers or a high-energy squeak titters.

As atoms vibrate in their lattices, they do so by either all moving in the same direction, in which case their collective vibration shows up as a low humming sound, or by moving in opposite directions from one another, giving rise to an energetic vibration that registers as a bright squeak or titter.

Why phonon vibrations matter
“These vibrations are crucial for both classical or quantum electronics,” said Hanyu Zhu, a corresponding author on a new study published in Physical Review Letters that reports an unus...

A thermal probe tests heat conductance in a sample of silicon dioxide nanoparticles. The material could potentially conduct heat at an efficiency higher than that of conventional materials. Credit: Rob Felt, Georgia Tech

Not beach sand, but silicon dioxide nanoparticles coated with a high dielectric constant polymer can inexpensively provide improved cooling for increasingly power-hungry electronic devices. The silicon dioxide doesn’t do the cooling itself. Instead, the unique surface properties of the coated nanoscale material conduct the heat at potentially higher efficiency than existing heat sink materials. The theoretical physics is complicated, involving nanoscale electromagnetic effects created on the surface of the tiny silicon dioxide particles acting together.

The bottom line cou...