Realization of a tunable artificial atom at a supercritically charged vacancy in graphene

Jinhai Mao, Yuhang Jiang, Dean Moldovan, Guohong Li, Kenji Watanabe, Takashi Taniguchi, Massoud Ramezani Masir, Francois M. Peeters, Eva Y. Andrei

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

Graphene's remarkable electronic properties have fuelled the vision of a graphene-based platform for lighter, faster and smarter electronics and computing applications. One of the challenges is to devise ways to tailor graphene's electronic properties and to control its charge carriers. Here we show that a single-atom vacancy in graphene can stably host a local charge and that this charge can be gradually built up by applying voltage pulses with the tip of a scanning tunnelling microscope. The response of the conduction electrons in graphene to the local charge is monitored with scanning tunnelling and Landau level spectroscopy, and compared to numerical simulations. As the charge is increased, its interaction with the conduction electrons undergoes a transition into a supercritical regime where itinerant electrons are trapped in a sequence of quasi-bound states which resemble an artificial atom. The quasi-bound electron states are detected by a strong enhancement of the density of states within a disc centred on the vacancy site which is surrounded by halo of hole states. We further show that the quasi-bound states at the vacancy site are gate tunable and that the trapping mechanism can be turned on and off, providing a mechanism to control and guide electrons in graphene.

Original languageEnglish (US)
Pages (from-to)545-549
Number of pages5
JournalNature Physics
Volume12
Issue number6
DOIs
StatePublished - Jun 1 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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