In JoVE (1)
Other Publications (1)
Articles by Dillon Wong in JoVE
Fabrication of Gate-tunable Graphene Devices for Scanning Tunneling Microscopy Studies with Coulomb Impurities Han Sae Jung1,2, Hsin-Zon Tsai1, Dillon Wong1, Chad Germany1, Salman Kahn1, Youngkyou Kim1,3, Andrew S. Aikawa1, Dhruv K. Desai1, Griffin F. Rodgers1, Aaron J. Bradley1, Jairo Velasco Jr.1, Kenji Watanabe4, Takashi Taniguchi4, Feng Wang1,5,6, Alex Zettl1,5,6, Michael F. Crommie1,5,6 1Department of Physics, University of California at Berkeley, 2Department of Chemistry, University of California at Berkeley, 3Department of Chemical and Biomolecular Engineering, University of California at Berkeley, 4National Institute for Materials Science (Japan), 5Materials Sciences Division, Lawrence Berkeley National Laboratory, 6Kavli Energy NanoSciences Institute, University of California at Berkeley and Lawrence Berkeley National Laboratory This paper details the fabrication process of a gate-tunable graphene device, decorated with Coulomb impurities for scanning tunneling microscopy studies. Mapping the spatially dependent electronic structure of graphene in the presence of charged impurities unveils the unique behavior of its relativistic charge carriers in response to a local Coulomb potential.
Other articles by Dillon Wong on PubMed
Observing Atomic Collapse Resonances in Artificial Nuclei on Graphene Science (New York, N.Y.). May, 2013 | Pubmed ID: 23470728 Relativistic quantum mechanics predicts that when the charge of a superheavy atomic nucleus surpasses a certain threshold, the resulting strong Coulomb field causes an unusual atomic collapse state; this state exhibits an electron wave function component that falls toward the nucleus, as well as a positron component that escapes to infinity. In graphene, where charge carriers behave as massless relativistic particles, it has been predicted that highly charged impurities should exhibit resonances corresponding to these atomic collapse states. We have observed the formation of such resonances around artificial nuclei (clusters of charged calcium dimers) fabricated on gated graphene devices via atomic manipulation with a scanning tunneling microscope. The energy and spatial dependence of the atomic collapse state measured with scanning tunneling microscopy revealed unexpected behavior when occupied by electrons.