Effective Mass of Quasiparticles in Armchair Graphene Nanoribbons

Abstract

Armchair graphene nanoribbons (AGNRs) may present intrinsic semiconducting bandgaps, being of potential interest in developing new organic-based optoelectronic devices. The induction of a bandgap in AGNRs results from quantum confinement effects, which reduce charge mobility. In this sense, quasiparticles’ effective mass becomes relevant for the understanding of charge transport in these systems. In the present work, we theoretically investigate the drift of different quasiparticle species in AGNRs employing a 2D generalization of the Su-Schrieffer-Heeger Hamiltonian. Remarkably, our findings reveal that the effective mass strongly depends on the nanoribbon width and its value can reach 60 times the mass of one electron for narrow lattices. Such underlying property for quasiparticles, within the framework of gap tuning engineering in AGNRs, impact the design of their electronic devices.

Regulating Polaron Transport Regime via Heterojunction Engineering in Cove‐Type Graphene Nanoribbons

“…Under a constant electric field regime, the resulting trajectory $$X(t)$$ could be modeled through projectile dynamics of a single particle of effective mass $$M_{\text{eff}}$$ subjected to a linear Stokes‐type dissipation. The solution of the corresponding equation of motion is [ 21,50 ] $$$$\begin{equation} X(t) = X_{0} + v_{\text{t}}t +\frac{v_{0} - v_{\text{t}}}{k}(1-\text{e}^{-kt}) \end{equation}$$$$where X 0 and v 0 are, respectively, the carrier's position and velocity at the instant that the field becomes constant ($$t=0$$). In addition, $$v_{t}$$ is the terminal velocity and $$k=B/M_{\text{eff}}$$, where B is the Stokes dissipation coefficient.…”

“…Under a constant electric field regime, the resulting trajectory X(t) could be modeled through projectile dynamics of a single particle of effective mass M eff subjected to a linear Stokes-type dissipation. The solution of the corresponding equation of motion is [21,50]…”

“…Under this formalism, charge transport is modeled as the drifting of a localized collective excitation along the lattice. The use of similar approaches yielded insightful results for other edge symmetries, [39,[41][42][43]50] polymeric systems [40,44,51] and crystalline arrangements under the Holsteinpolaron modeling for intermolecular transport. [52][53][54] In this work, we assessed the effects on transport and electronic properties due to the heterojunction engineering of cove-type graphene nanoribbons with different zigzag segments as building blocks.…”

“…Under this formalism, charge transport is modeled as the drifting of a localized collective excitation along the lattice. The use of similar approaches yielded insightful results for other edge symmetries, [ 39,41–43,50 ] polymeric systems [ 40,44,51 ] and crystalline arrangements under the Holstein‐polaron modeling for intermolecular transport. [ 52–54 ]…”

Width effects on bilayer graphene nanoribbon polarons

“…Besides the presented spatial and electronic properties of the polaron states, a complete overview of the charge transport performance requires the simulation of non-adiabatic dynamics with an external electric field, which is proven to provide crucial insights regarding dynamical mechanisms and the overall potential of the material for nanoelectronic applications. 28,30,35,36,39,[60][61][62] It should be noted that the decaying trend of D is not expected to hold indefinitely. In a high-pressure regime (high t > ), the modeling should be revised to include competing interactions such as Coulomb repulsion between layers, as evidenced in a previous study.…”