Credit: Image courtesy of Eva Andrei, Rutgers University
Starting with a missing atom, referred to as a vacancy (top left), and applying an electric charge that attracts electrons to the region, the electrons are confined into “orbitals” to create an “artificial atom” (lower right). The images are electron concentration maps obtained with scanning tunneling spectroscopy that visualize the vacancy, and then the electron orbitals (in red) of an artificial atom created in graphene. R1, R1’ and R2 show the orbitals in order of increasing energy.