Metallic bands in chevron-type polyacenes

Kher-Elden, M. A.; Piquero-Zulaica, Ignacio; El-Aziz, Kamel M. Abd; Ortega, J. Enrique; El-Fattah, Zakaria M. Abd

doi:10.1039/d0ra06007k

Cited by 5 publications

(3 citation statements)

References 63 publications

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“… 47 , 48 . First, we can see a decent agreement between the orbitals shape of coronene obtained by our EPWE approach (a) and DFT calculations (d), reassuring the suitability of EPWE for the exploration of finite GQDs 21 , 22 . Most importantly, the orbital shapes resemble those obtained for the metallic quantum dots (b, c), where the hexagonal MQD revealed excellent matching with EPWE and DFT calculations for coronene.…”

Section: Resultssupporting

confidence: 64%

“…Moreover, the same approach, i.e., the confinement of metallic free electron into honeycomb pathways, has been utilized later to model the electronic structure of atomistic graphene to density functional theory (DFT) level of accuracy using the scattering potential as a single fitting parameter 21 . This simplified nearly free electron approach remains valid for graphene nanostructures 21 , carbon-based organic molecules 22 , and other 2D materials such as hexagonal boron nitride 23 . Similarly, the discretization of the electronic structure in small graphene QDs, such as molecular coronone, could be well reproduced from confined electrons in smooth and/or atomically corrugated quantum wells, where the spectral intensity as probed with angle resolved photoemission (ARPES) as well as the frontier orbitals coincides with DFT calculations 24 .…”

Section: Introductionmentioning

confidence: 99%

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Analogous electronic states in graphene and planer metallic quantum dots

Othman,

Kher-Elden,

Ibraheem

et al. 2024

Sci Rep

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Graphene nanostructures offer wide range of applications due to their distinguished and tunable electronic properties. Recently, atomic and molecular graphene were modeled following simple free-electron scattering by periodic muffin tin potential leading to remarkable agreement with density functional theory. Here we extend the analogy of the $$\pi$$ π -electronic structures and quantum effects between atomic graphene quantum dots (QDs) and homogeneous planer metallic counterparts of similar size and shape. Specifically, we show that at high binding energies, below the $$\overline{M}$$ M ¯ -point gap, graphene QDs enclose confined states and standing wave quasiparticle interference patterns analogous to those reported on coinage metal surfaces for nanoscale confining structures such as vacancy islands and quantum corrals. These confined and quantum corral-like states in graphene QDs can be resolved in tomography experiments using angle-resolved photoemission spectroscopy. Likewise, the shape of near-Fermi frontier orbitals in graphene quantum dots can be reproduced from electron confinement within homogeneous metal QDs of identical size and shape. Furthermore, confined states analogous to those found in metallic quantum stadiums can be realized in coupled QDs of graphene for reduced separation. The present study offer a simple fundamental understanding of graphene electronic structures and also open the way towards efficient modeling of novel graphene-based nanostructures.

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Section: Resultssupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Analogous electronic states in graphene and planer metallic quantum dots

Othman,

Kher-Elden,

Ibraheem

et al. 2024

Sci Rep

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“…The analyzed organic and metal-organic systems require the use of the EBEM for finite structures (LDOS) and/or the EPWE for periodic arrays (Bloch-wave states) (García de Abajo et al, 2010;Klappenberger et al, 2011;Abd El-Fattah et al, 2019). Note that EPWE developed as a predictive tool not only for single layer molecular networks on surfaces but also for atomic 2D materials (such as graphene and h-BN), GNRs, polymers, and single molecules (Piquero-Zulaica et al, 2018;Abd El-Fattah et al, 2019;Kher-Elden et al, 2020;Ali et al, 2021).…”

Section: Edcs Atmentioning

confidence: 99%

Engineering quantum states and electronic landscapes through surface molecular nanoarchitectures

et al. 2022

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Surfaces are at the frontier of every known solid. They provide versatile supports for functional nanostructures and mediate essential physicochemical processes. Intimately related to two-dimensional materials, interfaces and atomically thin films often feature distinct electronic states with respect to the bulk, which is key to many relevant properties, such as catalytic activity, interfacial charge-transfer, and crystal growth mechanisms. To induce novel quantum properties via lateral scattering and confinement, reducing the surface electrons' dimensionality and spread with atomic precision is of particular interest. Both atomic manipulation and supramolecular principles provide access to custom-designed molecular assemblies and superlattices, which tailor the surface electronic landscape and influence fundamental chemical and physical properties at the nanoscale. Here the confinement of surface-state electrons is reviewed, with a focus on their interaction with molecular scaffolds created by molecular manipulation and self-assembly protocols under ultrahigh vacuum conditions. Starting with the quasifree twodimensional electron gas present at the ð111Þ-oriented surface planes of noble metals, the intriguing molecule-based structural complexity and versatility is illustrated. Surveyed are low-dimensional confining structures in the form of artificial lattices, molecular nanogratings, or quantum dot arrays, which are constructed upon an appropriate choice of their building constituents. Whenever the realized (metal-)organic networks exhibit long-range order, modified surface band structures with characteristic features emerge, inducing noteworthy physical phenomena such as discretization, quantum coupling or energy, and effective mass renormalization. Such collective electronic states can be additionally modified by positioning guest species at the voids of open nanoarchitectures. The designed scattering potential landscapes can be described with semiempirical models, bringing thus the prospect of total control over surface electron confinement and novel quantum states within reach.

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