Indirect exchange mechanism (IMAGE) University of Vienna Caption Indirect exchange mechanism for the electron-beam manipulation of bismuth or antimony dopants in silicon based on computer simulations. The crimson sphere is a bismuth atom, while yellow and green spheres are respectively its nearest and next-nearest silicon neighbours. Credit © Toma Susi & Alexander Markevich / University of Vienna, Andrew R. Lupini Usage Restrictions Credit must be given to the creator. License CC BY 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.