Tiago de Sousa Araújo Cassiano
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Fábio Ferreira Monteiro
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Pedro Henrique de Oliveira Neto
Since its isolation in 2004, graphene has attracted the attention of many scientists due to its excellent transport and mechanical features. However, the use of this material in optoelectronics is limited since it has no bandgap. One can detour it by cutting a graphene sheet laterally. The new carbon nanostructure that emerges from this procedure is known as graphene nanoribbon (GNR). Nowadays, a quest to develop a viable production of these materials drives many researchers. Narita et al.[2] successfully synthesized a candidate using a bottom-up solution procedure, known as cove-type GNR. Despite all the promising attributes, the electronic transport mechanism of this material is so far unexplored. In this work, we investigated through computational simulations the electronic transport of the cove-type GNR. We did so by employing an extended two-dimensional SSH model [3] with a tight-binding effect (electron-phonon coupling). A self-consistent field method generates stationary states, while time evolution is conducted based on the Ehrenfest theorem. Results reveal the formation of two polarized regions after photoionization: a polaron and a bipolaron. These quasiparticles are mobile by the application of a uniform electric field, unveiling its role as a charge transporter. Finally, a semi-classical algorithm evaluates their mobility and effective mass. Calculations indicate that both structures have a low effective mass along with intrinsic mobility. Hence, the cove-type GNRs may be suitable to perform as highly efficient semiconductors in future applications. This study contributes as well to the theoretical understanding of confined quantum systems.
Unveiling the Dynamics of Quasiparticles in Cove-type Graphene Nanoribbons
