Credit: Image courtesy of Lawrence Berkeley National Laboratory
Trapped electrons that follow the rules of relativistic quantum mechanics were directly imaged, validating theoretical predictions that these electrons traveling at near the speed of light can tunnel through energy barriers. The map shows the circular interference patterns of a graphene quantum dot, where the standing wave near the center of the dot arises from confined electronic states. This 300- by 300-nanometer map, representing a region that is a fraction of the size of the head of a pin, was obtained with a scanning tunneling microscope. The contrast corresponds to differences in conductance.