Electron hole state (IMAGE) ETH Zurich Caption In two graphene double layers twisted relative to each other (red and blue), insulating states consisting of electron-hole pairs (‘-‘ and ‘+’) can form. Credit Peter Rickhaus / ETH Zurich Usage Restrictions The rights to the images always remain with the person referred to as the copyright holder for them. Images published on ETH News may be used by other media and online portals only if ETH Zurich is specifically mentioned as the copyright holder and only in connection with the relevant ETH News article. Further distribution of images – for example, via download links – is permitted only with the approval of the editorial team. 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.