Mapping Impurities (IMAGE) Arizona State University Caption These are two plots of quantum capacitance as a function of potential. In a) various theoretical predictions of quantum capacitance are shown for graphene samples from pure, (the bottom V-shaped plot) to those above, indicating successively greater levels of impurity. In b) the red curve indicates theoretical prediction of quantum capacitance in graphene as a function of potential. The blue line shows the closely matching results of experimental measurements. Variations from theoretical ideal are the result of charged impurities in the graphene sample. Credit The Biodesign Institute at Arizona State 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.