Polaron and bipolaron possibility in graphene nanoribons via laser

Kenfack-Sadem, C.; Fobasso, M. F. C.; Amo-Mensah, F.; Baloïtcha, Ezinvi; Fotué, A. J.; Fai, Lukong Cornelius

doi:10.1016/j.physe.2020.114154

Cited by 14 publications

(8 citation statements)

References 43 publications

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“…For small polaron, the carriers localized over a or few bond lengths, with a low mobility that generally increases with temperature due to thermally activated phonon-assisted hopping from one localized site to another. 51 The small polaron has been observed in numerous compounds including metal oxides 52,53 and organic semiconductors 54 besides halide perovskites, and the possible existence of polaron formation in graphene and TMDs has been proposed based on theoretical investigation [55][56][57] . Strong e-ph interaction is indispensable in polaron formation and the small polaron emerges because of the strong and short-range e-ph coupling.…”

Section: Discussionmentioning

confidence: 99%

Observation of Negative Terahertz Photoconductivity in Large Area Type-II Dirac Semimetal PtTe2

et al. 2021

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As a newly emergent type-II Dirac semimetal, Platinum Telluride (PtTe 2 ) stands out from other 2D noble-transition-metal dichalcogenides for the unique structure and novel physical properties, such as high carrier mobility, strong electron-phonon coupling and tunable bandgap, which make the PtTe 2 a good candidate for applications in optoelectronics, valleytronics and far infrared detectors. Although the transport properties of PtTe 2 have been studied extensively, the dynamics of the nonequilibrium carriers remain nearly uninvestigated. Herein we employ optical pump-terahertz (THz) probe spectroscopy (OPTP) to systematically study the 2 photocarrier dynamics of PtTe 2 thin films with varying pump fluence, temperature, and film thickness. Upon photoexcitation the THz photoconductivity (PC) of 5 nm PtTe 2 film shows abrupt increase initially, while the THz PC changes into negative value in a subpicosecond time scale, followed by a prolonged recovery process that lasted hundreds of picoseconds (ps). This unusual THz PC response observed in the 5 nm PtTe 2 film was found to be absent in a 2 nm PtTe 2 film. We assign the unexpected negative THz PC as the small polaron formation due to the strong electron-E g -mode phonon coupling, which is further substantiated by pump fluence-and temperature-dependent measurements as well as the Raman spectroscopy. Moreover, our investigations give a subpicosecond time scale of sequential carrier cooling and polaron formation. The present study provides deep insights into the underlying dynamics evolution mechanisms of photocarrier in type-II Dirac semimetal upon photoexcitation, which is fundamental importance for designing PtTe 2 -based optoelectronic devices.

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Section: Discussionmentioning

confidence: 99%

Observation of Negative Terahertz Photoconductivity in Large Area Type-II Dirac Semimetal PtTe2

et al. 2021

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“…123 The possibility of quasiparticle-mediated charge transportnotably through polarons -has been extensively studied on the tight-binding level of theory. [155][156][157][158][159][160][161][162][163][164][165] It was found that stable polarons might form in narrow (N r 8) AGNRs. 157 In addition, interactions of these polarons with defects have been investigated and it was found that while some defects fully transmit polarons, others can reflect them.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Atomically precise graphene nanoribbons: interplay of structural and electronic properties

2021

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“…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.…”

Section: Introductionmentioning

confidence: 98%

“…The use of similar approaches yielded insightful results for other edge symmetries and polymeric systems. [39][40][41][42][43][44] Several modelings were developed to simulate intramolecular charge transport. For instance, DFT-based studies use the deformation potential theory combined with the semiclassical Boltzmann transport equation to estimate the carrier's effective mass and mobility in a free carrier picture that only considers the acoustic phonons.…”

Section: Introductionmentioning

confidence: 99%

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

Cassiano

Ribeiro

Silva

et al. 2023

Advcd Theory and Sims

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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.

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Polaron and bipolaron possibility in graphene nanoribons via laser

Cited by 14 publications

References 43 publications

Observation of Negative Terahertz Photoconductivity in Large Area Type-II Dirac Semimetal PtTe2

Observation of Negative Terahertz Photoconductivity in Large Area Type-II Dirac Semimetal PtTe2

Atomically precise graphene nanoribbons: interplay of structural and electronic properties

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

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