Interactions of slowly moving charges with graphene: The role of substrate phonons

Radović, Ivan; Jovanović, V. Borka; Borka, D.; Mišković, Z. L.

doi:10.1016/j.nimb.2011.10.028

Cited by 13 publications

(3 citation statements)

References 23 publications

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“…From Eqs. (16), (18), (23), and (24) of Ref. [50] it can be shown that the Fourier transform of the screened Coulomb interaction in the plane in which z = z = a/2 can be written as…”

Section: A Modeling Of the Systemmentioning

confidence: 99%

“…As far as the two-dimensional (2D) conductive materials are concerned, the wake effect was first studied theoretically in a strongly coupled 2D electron gas by Wang and Ma [15], followed by several studies of the wake effect in carbon nanostructures, including carbon nanotubes [16] and graphene [17][18][19][20][21][22][23]. For the latter material, the wake effect was also studied in the presence of plasmon-phonon hybridization taking place between graphene and a polar substrate [24] for both isolated [25] and correlated [26] charged particles moving parallel to graphene. There have been other investigations of the wake effect, e.g., in the case of dust grains in flowing plasma, [27] where an analogy was established with the Mach cone formation, as well as in the case of a 2D electron gas with defects, where plasmon excitation was caused by microwave radiation [28].…”

Section: Introductionmentioning

confidence: 99%

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Wake potential in graphene-insulator-graphene composite systems

et al. 2019

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We study the wake potential produced by an external charged particle that moves parallel to various sy 1-Al 2 O 3-sy 2 sandwich-like composites, where the system sy i (with i = 1, 2) may be vacuum, pristine graphene, or doped graphene. The effective dielectric function of the composites is obtained using three complementary methods for graphene's electronic response, based on the massless Dirac fermions (MDF) method, the extended hydrodynamic (eHD) model, and the ab initio approach. Three velocity regimes are explored with respect to the threshold for excitations of the Dirac plasmon in graphene, given by its Fermi velocity v F. In the low-velocity regime (below v F), only the transverse optical (TO) phonons in the Al 2 O 3 layer contribute to the wake potential in the surface with sy 2 (which is nearest to the charged particle), in a manner that is only sensitive to the composition of that system: if sy 2 is vacuum, the TO phonons give rise to intense oscillations in the wake potential, which are strongly suppressed if sy 2 is pristine or doped graphene. For intermediate velocities (above v F), the hybridized plasmon-TO phonon modes on both surfaces contribute to the wake potential in the surface with sy 2 , with the most dominant contribution coming from the hybridized Dirac-like plasmonic modes. In the high-velocity regime (well above v F), the highest-lying hybridized Dirac plasmon gives the dominant contribution to the wake potential, which exhibits a typical V-shaped wave-front pattern that lags behind the charged particle. It is found that the MDF method agrees very well with the results of the ab initio method for small and intermediate velocities. However, in the high-velocity regime, the high-energy π plasmon in graphene introduces new features in the wake potential in the form of fast oscillations, just behind the charged particle. Those oscillations in the wake potential are well described by both the eHD and the ab initio method, proving that the π plasmon indeed behaves as a collective mode.

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“…From Eqs. (16), (18), (23), and (24) of Ref. [50] it can be shown that the Fourier transform of the screened Coulomb interaction in the plane in which z = z = a/2 can be written as…”

Section: A Modeling Of the Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Wake potential in graphene-insulator-graphene composite systems

et al. 2019

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“…Therefore, it is expected that occurrence of the wake effect in the LEIGS may be particularly sensitive to the plasmonphonon hybridization, which would almost certainly affect this threshold velocity effect. We note that the effects of optical phonons in a polar substrate were recently studied for charged particles moving parallel to an epitaxial graphene layer grown on a SiC substrate [20,33], which only exhibits one strong surface phonon in the THz to mid-IR range. However, most applications of graphene that are expected to benefit from its tunability by charge doping employ SiO 2 as an insulating layer [9,11,12], which exhibits two prominent surface optical phonon modes in the relevant range of frequencies.…”

Section: Introductionmentioning

confidence: 96%

Probing the Plasmon-Phonon Hybridization in Supported Graphene by Externally Moving Charged Particles

et al. 2015

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We use the dielectric response formalism to show how an incident charged particle may be used to probe the hybridization taking place between the Dirac plasmon in graphene and the surface optical phonon modes in a SiO 2 substrate. Strong effects of this hybridization are found in the wake pattern in the induced potential, as well as in the stopping and image forces that act on the incident charge in a broad range of its velocities. Particularly intriguing is the possibility to control the plasmon-phonon hybridization by varying the doping density of graphene, where the regime of a nominally neutral graphene is expected to give rise to dramatic effects in the energy loss of charged particles that move at the velocities below the Fermi velocity of graphene.

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