2D 1 (IMAGE) Rice University Caption Electrets -- electrons trapped in defects in two-dimensional molybdenum dioxide -- give the material piezoelectric properties, according to Rice University researchers. The defects (blue) appear in the material during formation in a furnace, and generate an electric field when under pressure. Credit Ajayan Research Group/Rice University Usage Restrictions None 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.