Atomic Layers (IMAGE) University of Utah Caption Deshpande and his team created devices using 3-D TIs by stacking five few-atom-thin layers of various materials into sloppy sandwich-like structures. The core of the sandwich is the topological insulator, made from a few quintuple layers of bismuth antimony tellurium selenide (Bi2-xSbxTe3-ySey). Credit Su Kong Chong Usage Restrictions non commercial with attribution License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.