Dynamics of charge carriers on hexagonal nanoribbons with vacancy defects

Silva

Sousa

et al. 2018

Sci Rep

The dynamical properties of polarons in armchair graphene nanoribbons (GNR) is numerically investigated in the framework of a two-dimensional tight-binding model that considers spin-orbit (SO) coupling and electron-lattice (e-l) interactions. Within this physical picture, novel polaron properties with no counterparts to results obtained from conventional tight-binding models are obtained. Our findings show that, depending on the system’s width, the presence of SO coupling changes the polaron’s charge localization giving rise to different degrees of stability for the charge carrier. For instance, the joint action of SO coupling and e-l interactions could promote a slight increase on the charge concentration in the center of the lattice deformation associated to the polaron. As a straightforward consequence, this process of increasing stability would lead to a depreciation in the polaron’s motion by decreasing its saturation velocity. Our finds are in good agreement with recent experimental investigations for the charge localization in GNR, mostly when it comes to the influence of SO coupling. Moreover, the contributions reported here provide a reliable method for future works to evaluate spin-orbit influence on the performance of graphene nanoribbons.

Section: Resultssupporting

confidence: 87%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Spin-Orbit Effects on the Dynamical Properties of Polarons in Graphene Nanoribbons

Silva

Sousa

et al. 2018

Sci Rep

“…From Fig. 1(a) one can realize that, during the first 100 fs, the strength of the electric field is turned on quasi-adiabatically – following the procedure established in refs 36,37 – to preserve numerical stability. After this transient period, the bipolarons are accelerated and reach their saturation velocity at around 400 fs.…”

Section: Resultsmentioning

confidence: 99%

Charge Carrier Scattering in Polymers: A New Neutral Coupled Soliton Channel

Monteiro

Cunha

et al. 2018

Sci Rep

The dynamical scattering of two oppositely charged bipolarons in non-degenerate organic semiconducting lattices is numerically investigated in the framework of a one-dimensional tight-biding–Hubbard model that includes lattice relaxation. Our findings show that it is possible for the bipolaron pair to merge into a state composed of a confined soliton-antisoliton pair, which is characterized by the appearance of states within less than 0.1 eV from the Fermi level. This compound is in a narrow analogy to a meson confining a quark-antiquark pair. Interestingly, solitons are quasi-particles theoretically predicted to arise only in polymer lattices with degenerate ground state: in the general case of non-degenerate ground state polymers, isolated solitons are not allowed.

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

Cassiano

Silva

et al. 2023

Advcd Theory and Sims

Graphene nanoribbons (GNRs) are emerging materials inheriting excellent properties from graphene while potentially exhibiting semiconducting behavior. All these features sparked numerous efforts to insert GNRs in nanoelectronics. As a result, synthesis routes with atomic resolution are now a reality. Recently, the rise of heterojunction (HJ) engineering pushed even further the prospects, allowing the blending of different GNRs as building blocks. However, much of the potential behind it remains untouched for some junctions. In this work, the consequences of forming a cove‐type GNR (CGNR) HJ by assembling specimens with borders of different zig‐zag/armchair ratios are explored. The nanoribbons are simulated using the extended two‐dimensional Su–Schrieffer–Heeger model with electron–phonon coupling. The findings show that manipulating the junction creates multiple routes for smooth monotonic gap tuning. Moreover, the changes in the hopping mechanism, mobility, and effective mass are reported leading to variations up to 10 000 cm2 V−1 s−1 and 0.425 me. This work reveals a pathway to expand the modularity of CGNRs through smooth control of the charge carrier's properties. Future applications can explore this feature to design devices with highly specific charge transport characteristics. The study also serves as theoretical background, potentially inspiring new tuning strategies in other GNRs.