Electronics get hot. The more powerful the processor, the more heat you need to get rid of, or it will fail. One bottleneck is the boundary between two materials: heat hits it like a seam between tiles and slows down.
Scientists made the junction between aluminum nitride and silicon carbide almost perfectly smooth, with no gaps at all. Heat passes through it with almost no loss. It's like a tile seam so smooth that water flows over it without pausing.
This approach could help build more powerful and reliable electronic devices, from phones to electric cars.
The atomic vibrations that carry heat are called phonons, and at a very clean boundary they pass through almost without hindrance.