An Unexpected Third Material (IMAGE) North Carolina State University Caption Researchers have found that the gallium arsenide and bismuth telluride are actually separated by a thin layer of a hitherto unsuspected third material -- gallium telluride. The materials are held together by the weak forces of van der Waals bonds. Credit James LeBeau, North Carolina State University Usage Restrictions Image credit must be given. 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.