Coupling of Nondegenerate Topological Modes in Nitrogen Core-Doped Graphene Nanoribbons

Journal Article · Thu Mar 27 00:00:00 EDT 2025 · ACS Nano

DOI:https://doi.org/10.1021/acsnano.4c17602· OSTI ID:2540169

Jacobse, Peter H. ^[1]; Pizzochero, Michele ^[2]; Wen, Ethan Chi Ho ^[1]; Barin, Gabriela Borin ^[3]; Li, Xinheng ^[1]; Mutlu, Zafer ^[4]; Müllen, Klaus ^[5]; Kaxiras, Efthimios ^[6]; Crommie, Michael F. ^[7]; Fischer, Felix R. ^[7]

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1. University of California, Berkeley, CA (United States)
2. University of Bath (United Kingdom); Harvard University, Cambridge, MA (United States)
3. Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf (Switzerland)
4. University of Arizona, Tucson, AZ (United States)
5. Max Planck Institute for Polymer Research, Mainz (Germany)
6. Harvard University, Cambridge, MA (United States)
7. University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Nitrogen core-doping of graphene nanoribbons (GNRs) allows trigonal planar carbon atoms along the backbone of GNRs to be substituted by higher-valency nitrogen atoms. The excess valence electrons are injected into the π-orbital system of the GNR, thereby changing not only its electronic occupation but also its topological properties. We have observed this topological change by synthesizing dilute nitrogen core-doped armchair GNRs with a width of five atoms (N₂-5-AGNRs). The incorporation of pairs of trigonal planar nitrogen atoms results in the emergence of topological boundary states at the interface between doped and undoped segments of the GNR. These topological boundary states are offset in energy by approximately ΔE = 300 meV relative to the topological end states at the termini of finite 5-AGNRs. Scanning tunneling microscopy (STM) and spectroscopy (STS) reveal that for finite GNRs the two types of topological states can interact through a linear combination of orbitals, resulting in a pair of asymmetric hybridized states. This behavior is captured by an effective Hamiltonian of nondegenerate diatomic molecules, where the analogous interatomic hybridization interaction strength is tuned by the distance between GNR topological modes.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); University of California, Berkeley, CA (United States)
• Sponsoring Organization: National Institutes of Health (NIH); National Science Foundation (NSF); Office of Naval Research (ONR); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE)
• Grant/Contract Number: AC02-05CH11231; SC0023105
• OSTI ID: 2540169
• Alternate ID(s): OSTI ID: 2563697; OSTI ID: 2555761
• Journal Information: ACS Nano, Journal Name: ACS Nano Journal Issue: 13 Vol. 19; ISSN 1936-0851
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Hamiltonians
end states
energy
graphene nanoribbons
hybridization
nitrogen core-doping
scanning tunneling
scanning tunneling microscopy
topological modes
wave function
zero mode engineering