"Layering allows you to look for new properties; making sharp interfaces between the different layers allows them to influence each other in unique ways," Santos said.
The device is ringed with canisters, each containing different pure metals that can be heated to more than 2,500 degrees Fahrenheit—so hot they actually evaporate. The beam of evaporated metal atoms shoots into a central chamber under an ultra-high vacuum. There it meets beams of different metals, hits a substrate and reacts with oxygen to form a compound in perfectly structured crystalline layers. Then the scientists can repeat the process to add more layers.