Edge and passivation effects in armchair graphene nanoribbons

Raza, Hassan

doi:10.1103/physrevb.84.165425

Cited by 42 publications

(60 citation statements)

References 45 publications

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“…These two modes of the homodimers are excited, respectively, when the electron beam passes by the dimers at their edge and gap center. Firstly, we investigate the EELS spectra of the dimers by numerical calculations using a classical local model, a hydrodynamic nonlocal model, [52,[71][72][73] and a quantum-corrected model (QCM). [43,74] By analyzing the resonant energy and EELS intensity of the two modes as a function of gap size, we demonstrate that the spatial nonlocality and electron tunneling effects affect the BDM and ADM properties in quite different manners.…”

Section: Introductionmentioning

confidence: 99%

Electron Energy‐Loss Spectroscopy of Spatial Nonlocality and Quantum Tunneling Effects in the Bright and Dark Plasmon Modes of Gold Nanosphere Dimers

Zhang

Cai

et al. 2018

Adv Quantum Tech

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Herein, a theoretical and experimental electron energy‐loss spectroscopy (EELS) study on gold nanosphere dimers is presented, with interparticle distance d of the dimers varying from 10 nm to a few angstroms. Injecting an electron beam at the edge or the gap of the dimers excites their longitudinal bonding dipolar mode (BDM) or antibonding dipolar mode (ADM), respectively. Together with comprehensive EELS calculations within the frameworks of a classical local model, a hydrodynamic nonlocal model, and a quantum‐corrected model (QCM), it is revealed that spatial nonlocality and electron tunneling have distinctively different effects on the plasmonic properties of BDM and ADM, such as resonant energy and intensity variation. Specifically, the spatial nonlocality effect blue‐shifts the BDM energy and decreases its EELS intensity at d < 3 nm compared to the classical local results, while the electron tunneling effect induces a much weaker charge transfer mode (CTM) at d < 0.3 nm. However, both effects have little impact on the ADM energy though they indeed affect its EELS intensity in dramatically different manners. The experimental EELS spectra measured at varied gap size are qualitatively consistent with the numerical calculations. These results may contribute to further understanding of quantum mechanical effects in different kinds of hybridized plasmon modes in strongly coupled metallic nanostructures.

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Section: Introductionmentioning

confidence: 99%

Electron Energy‐Loss Spectroscopy of Spatial Nonlocality and Quantum Tunneling Effects in the Bright and Dark Plasmon Modes of Gold Nanosphere Dimers

Zhang

Cai

et al. 2018

Adv Quantum Tech

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“…The device structure is shown in Figure 1b, where the channel is gated by two side gates to create an electric field in the width direction. For such a side-gated nanoribbon, we show the electronic structure in Figure 1c using extended Hückel theory (see [8-12] for the detailed model). The two interesting electronic structure features are a significant band gap opening of about 2 eV, which is not very sensitive to the external electric field, and secondly a near-midgap state with a finite bandwidth, the bandwidth and dispersion of which can be manipulated by the gate-induced electric field.…”

Section: Methodsmentioning

confidence: 99%

Electronic structure modulation for low-power switching

Raza

2013

Nanoscale Res Lett

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We report the transport characteristics of a novel transistor based on the electronic structure modulation of the channel. The gate voltage-controlled current modulation arises from the bandwidth manipulation of a midgap or a near-midgap state. We show that the transistor exhibits a gain and overcomes the 2.3 kBT/decade thermal limit in the inverse subthreshold slope where kB is the Boltzmann constant. The unique device physics also opens up many novel applications.

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“…The advancement of sophisticated nano-fabrication techniques has recently allowed for the realization of atomically thin films, structures with extremely sharp angles and touching points 1-7 . The exotic behaviour of these singular structures hinges on small-scale geometrical features of nanometer and even sub-nanometer-scale, so that quantum effects, such as repulsion, diffusion and spill-out of electrons, become appreciable 2, [8][9][10][11] . In the case of noble metals, such as gold and silver, the nonlocal response is dominated by repulsion in the electron gas, resulting in size-dependent linewidth broadening and resonance shift.…”

Section: Introductionmentioning

confidence: 99%

Nonlocal effects in plasmonic metasurfaces with almost touching surfaces

et al. 2020

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Geometrical singularities in plasmonic metasurfaces have recently been proposed for the enhancement of light-matter interactions, owing to their broadband light-harvesting properties and extreme plasmon confinement. However, the large plasmon momenta thus achieved lead to failure of local descriptions of the optical response of metals. Here we study a class of metasurfaces consisting of a periodic metal slab with a smooth modulation of its thickness. When the thinnest part shrinks, the two surfaces almost touch, forming a near-singular point. Using transformation optics, we show analytically how nonlocal effects, such as a blueshift of the resonance peaks and a reduced density of states, become important and cannot be ignored in this singular regime. The method developed in this paper is very general and can be used to model a variety of metasurfaces, providing valuable insight in the current context of ultra-thin plasmonic structures. * f.yang16@imperial.ac.uk 1 arXiv :1912.11020v1 [cond-mat.mes-hall]

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Edge and passivation effects in armchair graphene nanoribbons

Cited by 42 publications

References 45 publications

Electron Energy‐Loss Spectroscopy of Spatial Nonlocality and Quantum Tunneling Effects in the Bright and Dark Plasmon Modes of Gold Nanosphere Dimers

Electron Energy‐Loss Spectroscopy of Spatial Nonlocality and Quantum Tunneling Effects in the Bright and Dark Plasmon Modes of Gold Nanosphere Dimers

Electronic structure modulation for low-power switching

Nonlocal effects in plasmonic metasurfaces with almost touching surfaces

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