<i>Ab initio</i>study of energy loss and wake potential in the vicinity of a graphene monolayer

Despoja, Vito; Dekanić, Krešimir; Šunjić, Marijan; Marušić, Leonardo

doi:10.1103/physrevb.86.165419

Cited by 37 publications

(43 citation statements)

References 34 publications

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“…The latter have been observed in some outstanding experiments on MLG [9,10] and few-layer graphene [9,11], while most of the theoretical work has been centered on MLG [12,13,[15][16][17][18][19]. As for the lowenergy end of the EL spectrum, a conventional 2D plasmon was predicted to exist and related anisotropic effects were analyzed in doped/gated (extrinsic) MLG and BLG [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 98%

“…Previous studies on few-layer graphene [9][10][11][12][13][15][16][17][18][19][20][21][22][23][24][25][26] have put the focus on the energy-loss (EL) spectrum, exploring both the high-energy part (up to ∼30 eV), where both interband excitations and collective modes lie, and the low-energy part (below ∼2 eV), where the spectral features are strongly influenced by the doping and by the presence of intraband excitations that should play an important role in modern plasmonic devices.…”

Section: Introductionmentioning

confidence: 99%

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Dielectric screening and plasmon resonances in bilayer graphene

et al. 2016

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The plasmon structure of intrinsic and extrinsic bilayer graphene is investigated in the framework of ab initio time-dependent density-functional theory (TDDFT) at the level of the random-phase approximation (RPA). A two-step scheme is adopted, where the electronic ground state of a periodically repeated slab of bilayer graphene is first determined with full inclusion of the anisotropic band structure and the interlayer interaction; a Dyson-like equation is then solved self-consistently in order to calculate the so-called density-response function of the many-electron system. A two-dimensional correction is subsequently applied in order to eliminate the artificial interaction between the replicas. The energy range below ∼30 eV is explored, focusing on the spectrum of single-particle excitations and plasmon resonances induced by external electrons or photons. The high-energy loss features of the π and σ + π plasmons, particularly their anisotropic dispersions, are predicted and discussed in relation with previous calculations and experiments performed on monolayer and bilayer graphene. At the low-energy end, the energy-loss function is found to be (i) very sensitive to the injected charge carrier density in doped bilayer graphene and (ii) highly anisotropic. Furthermore, various plasmon modes are predicted to exist and are analyzed with reference to the design of novel nanodevices.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Dielectric screening and plasmon resonances in bilayer graphene

et al. 2016

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“…The v GG terms have been proved to efficiently cut off the spurious interaction between replicas of planar graphenebased systems [18,[45][46][47]. Finally, the EL spectra were computed by…”

Section: Local Density Calculations and Geometry Optimizationmentioning

confidence: 99%

“…A serious drawback stems from the long-range character of the Coulomb potential, which allows nonnegligible interactions between repeated planar arrays even at large distances. To cut off this unwanted phenomenon, we replace v 0 GG by the truncated Fourier integral [18,19,[45][46][47] …”

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confidence: 99%

Plasmon Modes of Graphene Nanoribbons with Periodic Planar Arrangements

et al. 2016

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Among their amazing properties, graphene and related low-dimensional materials show quantized charge-density fluctuations-known as plasmons-when exposed to photons or electrons of suitable energies. Graphene nanoribbons offer an enhanced tunability of these resonant modes, due to their geometrically controllable band gaps. The formidable effort made over recent years in developing graphene-based technologies is however weakened by a lack of predictive modeling approaches that draw upon available ab initio methods. An example of such a framework is presented here, focusing on narrow-width graphene nanoribbons organized in periodic planar arrays. Time-dependent density-functional calculations reveal unprecedented plasmon modes of different nature at visible to infrared energies. Specifically, semimetallic (zigzag) nanoribbons display an intraband plasmon following the energy-momentum dispersion of a two-dimensional electron gas. Semiconducting (armchair) nanoribbons are instead characterized by two distinct intraband and interband plasmons, whose fascinating interplay is extremely responsive to either injection of charge carriers or increase in electronic temperature. These oscillations share some common trends with recent nanoinfrared imaging of confined edge and surface plasmon modes detected in graphene nanoribbons of 100-500 nm width. Plasmons are quantized oscillations of the valence electron density in metals, metal-dielectric interfaces and nanostructures, being usually excited by light or electronbeam radiation. Plasmon-related technologies are expected to receive a burst from nanocarbon architectures [1-10], due to one of the fascinating features of monolayer graphene (MG) [11], i.e., its extrinsic plasmon modes at terahertz (THz) frequencies [12][13][14][15][16][17][18][19][20]. These show much stronger confinement, larger tunability and lower losses [21] compared to conventional plasmonic materials, such as silver or gold. Nowadays plasmons are launched, controlled, manipulated and detected in a variety of graphene-related materials and heterostructures, which suggests that graphene-based plasmonic devices are becoming closer to reality, with the potential to operate on the "THz gap", forbidden by either classical electronics or photonics [4,22,23]. Plasmons with widely tunable frequencies have been observed in graphene nanoribbons (GNRs)-from the nano-to microrange in width [12,14,24,25]. On the theoretical side, density functional and tight-binding (TB) approaches have explored the electronic structure of zigzag and armchair GNRs, with particular attention to the band-gap values of the intrinsic systems, being a major control factor of their plasmonic properties [26][27][28][29][30]. Far fewer studies have been focused on plasmon resonances in GNRs using either a semiclassical electromagnetic picture [31] or a TB scheme [5,32,33], and specializing to THz frequencies. A comprehensive characterization of the dielectric properties of such systems is, however, lacking.Here, we provide an ab initio study o...

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“…[14][15][16] These low-energy plasmons, which appear at mid-infrared and lower frequencies, should not be confused with the higher-energy π and σ plasmons that show up in most carbon allotropes, and that have been extensively studied through electron energy-loss spectroscopy (EELS) in fullerenes, 17,18 nanotubes, 19 and graphene. [20][21][22][23] These high-energy plasmons are not electrically tunable. We thus concentrate on electrically driven low-energy plasmons in graphene.…”

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confidence: 99%

Even Hard-Sphere Colloidal Suspensions Display Fickian Yet Non-Gaussian Diffusion

2014

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We show that free electrons can efficiently excite plasmons in doped graphene with probabilities of order one per electron. More precisely, we predict multiple excitations of a single confined plasmon mode in graphene nanostructures. These unprecedentedly large electron-plasmon couplings are explained using a simple scaling law and further investigated through a general quantum description of the electron-plasmon interaction. From a fundamental viewpoint, multiple plasmon excitations by a single electron provides a unique tool for exploring the bosonic quantum nature of these collective modes. Our study does not only open a viable path towards multiple excitation of a single plasmon mode by single electrons, but it also reveals graphene nanostructures as ideal systems for producing, detecting, and manipulating plasmons using electron probes.

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Ab initiostudy of energy loss and wake potential in the vicinity of a graphene monolayer

Cited by 37 publications

References 34 publications

Dielectric screening and plasmon resonances in bilayer graphene

Dielectric screening and plasmon resonances in bilayer graphene

Plasmon Modes of Graphene Nanoribbons with Periodic Planar Arrangements

Even Hard-Sphere Colloidal Suspensions Display Fickian Yet Non-Gaussian Diffusion

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