Article
Version 1
Preserved in Portico This version is not peer-reviewed
Long Range Effects in Topologically Defective Arm-Chair Graphene Nanoribbons
Version 1
: Received: 13 December 2023 / Approved: 15 December 2023 / Online: 15 December 2023 (05:32:33 CET)
Version 2 : Received: 2 April 2024 / Approved: 3 April 2024 / Online: 3 April 2024 (08:17:05 CEST)
Version 2 : Received: 2 April 2024 / Approved: 3 April 2024 / Online: 3 April 2024 (08:17:05 CEST)
A peer-reviewed article of this Preprint also exists.
Louis, E.; Chiappe, G.; Vergés, J.A.; San-Fabián, E. Long-Range Effects in Topologically Defective Arm-Chair Graphene Nanoribbons. Nanomaterials 2024, 14, 778. Louis, E.; Chiappe, G.; Vergés, J.A.; San-Fabián, E. Long-Range Effects in Topologically Defective Arm-Chair Graphene Nanoribbons. Nanomaterials 2024, 14, 778.
Abstract
The electronic structure of 7/9-AGNR superlattices with up to eight unit cells has been studied by means of state of the art DFT and a model Hamiltonian that follows two different approaches: Hubbard type (Hu) and including long range Coulomb interaction (PPP), solved in the mean field approximation. We show that 7/9 interfaces stabilizes non polarized solutions at the mean field level. Considering non-polarized solutions, Hu and PPP Hamiltonians gives solutions with a gap that is closed as the size is increased. This is in line with DFT results. However the density of states around the Fermi level is not correctly described neither in Hu nor in the PPP model. We also interpret the DFT density of states in terms of bands of topological states: localized edge topological states and extended bulk topological states which interacts between them due to the long range Coulomb terms of Hamiltonian. In this line, we show that a screened long range interaction instead describe correctly DFT results and the interaction between topological states. Screening consists of introducing a parameter for an exponential decay in the long range potential of the model Hamiltonian, to vary its spatial range. Calculations on the superlattice just mentioned, illustrate the relevance of include appropriate long range interactions in determining the density of states around the Fermi level (Dirac point).
Keywords
graphene; nano-ribbons; long range effects
Subject
Chemistry and Materials Science, Theoretical Chemistry
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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