Fig. 1. (IMAGE) Forschungsverbund Berlin Caption Unit cell (a cube having an edge length of 0.56 nm [one millionth of 0.56 mm]) of gallium arsenide with gallium (black) and arsenic atoms (red) connected by covalent bonds (blue). A gallium arsenide crystal consists of many billions of such unit cells. Credit MBI Usage Restrictions The image may only be used with appropriate caption and credit. 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.