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TT: Fachverband Tiefe Temperaturen
TT 10: Nanotubes and Nanoribbons
TT 10.5: Vortrag
Montag, 16. März 2020, 12:30–12:45, HSZ 204
Correlated Topological States in Graphene Nanoribbon Heterostructures — •Jan-Philip Joost1, Antti-Pekka Jauho2, and Michael Bonitz1 — 1CAU Kiel, Germany — 2CNG, DTU Physics, Kongens Lyngby, Denmark
Finite graphene nanoribbon (GNR) heterostructures host intriguing topological in-gap states [1]. These states may be localized either at the bulk edges or at the ends of the structure. Here we show that correlation effects (not included in previous density functional simulations) play a key role in these systems: they result in increased magnetic moments at the ribbon edges accompanied by a significant energy renormalization of the topological end states, even in the presence of a metallic substrate [2].
We present simulations of 7-9-AGNRs based on a Green functions method with GW self-energy applied to an effective Hubbard model. Our computed results for the differential conductance are in excellent agreement with experimental observations [3]. Furthermore, we discover a striking, novel mechanism that causes an energy splitting of the nonzero-energy topological end states for a weakly screened system. We predict that similar effects should be observable in other GNR heterostructures as well.
[1] T. Cao et al., Phys. Rev. Lett. 119, 076401 (2017)
[2] J.-P. Joost, A.-P. Jauho, M. Bonitz, Nano Letters (2019), DOI:10.1021/acs.nanolett.9b04075
[3] D. J. Rizzo et al., Nature 560, 204-208 (2018)