2d diagram (IMAGE) Penn State Caption The two types of interfaces between layers of transition metal dichalcogenides (TMD) 2D materials where the top layer is a Janus TMD with two types of atoms (selenium and sulfur) and the bottom layer is a regular TMD with one type of atom (sulfur). The S/S interface is much stronger than the Se/S interface due to the charge distribution from the imbalance in S atoms. Credit Penn State Materials Research Institute Usage Restrictions non commercial use only License Original 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.