NCAFM2023 Programme Booklet

Mykola Telychko 1,* , Keian Noori 2,3 , Harshitra Mahalingam 4 , Hillol Biswas 3,5 , Dikshant Dulal 4 , Zhaolong Chen 2 , Pin Lyu 1 , Jing Li 1 , Hsin-Zon Tsai 5 , Hanyan Fang 1 , Zhizhan Qiu 1 , Zhun Wai Yap 4 , Kenji Watanabe 6 , Takashi Taniguchi 7 , Jing Wu 8 , Kian Ping Loh 1 , Michael F. Crommie 5 , Aleksandr Rodin 3,4,* , Jiong Lu 1,2,3,* GATE TUNABLE CORRELATION EFFECTS FOR PROTON LIKE ATOMIC CHARGES IN GRAPHENE

1 Department of Chemistry, National University of Singapore, 117543 Singapore 2 Institute for Functional Intelligent Materials, National University of Singapore, 117544, Singapore 3 Centre for Advanced 2D Materials (CA2DM), National University of Singapore, 117543, Singapore 4 Yale-NUS College, 16 College Avenue West, 138527, Singapore 5 Department of Physics, University of California, Berkeley, California 94720, USA.

6 Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan 7 International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan 8 Institute of Materials Research and Engineering, Agency for Science, Technology and Research, 08-03, 2 Fusionopolis Way, Singapore 138634, Singapore

Email: telychko@nus.edu.sg, aleksandr.rodin@yale-nus.edu.sg, chmluj@nus.edu.sg

The ability to create robust and well-defined artificial atomic charges in graphene and understand its carrier-dependent electronic and structural properties represents an important goal toward the development of graphene-based quantum devices. Herein, we present a new pathway towards atomically precise embodiment of single sp2-hybridized Nitrogen (N) and Oxygen (N) dopants into a back-gated graphene device via low-energy ion implantation, followed by evaluation of their structural and electronic properties via combined STM/ncAFM bond-resolved measurements. The single N dopant behaves as an in-plane proton-like charge manifested by formation of the characteristic resonance state in the conduction band [1]. Measurements at varied charge carrier densities reveal a giant energetic renormalization (220 meV) of the N-induced state with respect to the Dirac point. In stark contrast, O dopant reveals characteristic resonance state below Fermi level, that is energetically pinned to Dirac point and exhibits rigid shift with respect to back-gate voltage. We employed joint density functional theory and tight-binding calculations with modified perturbation potential to rationalize experimental findings.

Fig. SPM characterization of N and O dopants in back-gated graphene setup. a) Schematics showing route towards incorporation of N or O dopant into sgraphene using low-energy ion implantation; b) Large-scale STM image revealing presence of individual substitutional N atoms. Inset: STM/ncAFM images of substitutional O atom. c), d) set of dI/dV spectra acquired along line traversing N and O. References [1] M. Telychko, K. Noori, H.Biswas, D. Dulal, Z.Chen, P. Lyu, J. Li, H.-Z. Tsai, H. Fang, Z. Qiu, Z. Wai Yap, K. Watanabe, T. Taniguchi, J. Wu, K. Ping Loh, M. F. Crommie, A. Rodin*, J. Lu*, Nano Letters, 2022, 22, 21 , 8422–8429

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