Moving heat around where you want it to go -- adding it to houses and hairdryers, removing it from car engines and refrigerators -- is one of the great challenges of engineering.
All activity generates heat, because energy escapes from everything we do. But too much can wear out batteries and electronic components -- like parts in an aging laptop that runs too hot to actually sit on your lap. If you can't get rid of heat, you've got a problem.
Scientists at the University of Chicago have invented a new way to funnel heat around at the microscopic level: a thermal insulator made using an innovative technique. They stack ultra-thin layers of crystalline sheets on top of each other, but rotate each layer slightly, creating a material with atoms that are aligned in one direction but not in the other.
"Think of a partly-finished Rubik's cube, with layers all rotated in random directions," said Shi En Kim, a graduate student with the Pritzker School of Molecular Engineering who is the first author of the study. "What that means is that within each layer of the crystal, we still have an ordered lattice of atoms, but if you move to the neighboring layer, you have no idea where the next atoms will be relative to the previous layer -- the atoms are completely messy along this direction."
The result is a material that is extremely good at both containing heat and moving it, albeit in different directions -- an unusual ability at the microscale, and one that could have very useful applications in electronics and other technology.
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