Simplified theory of the acoustic surface plasmons at the two-dimentional electron gas

Ahn, Jong-Kwan; Kim, Yon-Il; Kim, Kwang‐Hyon; Kang, Chol-Jin; Ri, Myong Chol; Kim, Song-Hyok

doi:10.1016/j.physb.2015.11.020

Cited by 4 publications

(3 citation statements)

References 16 publications

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“…The reliable calculation of these phenomena is still a challenge for simulations, as seen by two conflicting predictions for the Ag (111) surface: according to Ref. [90] this system should exhibit a slope even higher than for Au (111), while the non ab initio theory predicts a slope even lower than on Cu (111), in agreement with a third, independent calculation [91]. No experiments have measured the ASP dispersion for Ag (111) yet, so that this controversy remains open.…”

Section: Systemmentioning

confidence: 86%

Plasmons in one and two dimensions

Pfnür¹,

Tegenkamp²,

Vattuone³

2017

Preprint

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Plasmons in low-dimensional systems respresent an important tool for coupling energy into nanostructures and the localization of energy on the scale of only a few nanometers. Contrary to ordinary surface plasmons of metallic bulk materials, their dispersion goes to zero in the long wavelength limit, thus covering a broad range of energies from terahertz to near infrared, and from mesoscopic wavelengths down to just a few nanometers. Using specific and most characteristic examples, we review first the properties of plasmons in two-dimensional (2D) metallic layers from an experimental point of view. As demonstrated, tuning of their dispersion is possible by changes of charge carrier concentration in the partially filled 2D conduction bands, but for the relativistic electron gas like in graphene only in the long wavelength limit. For short wavelengths, on the other hand, the dispersion turns out to be independent of the position of the Fermi level with respect to the Dirac point. A linear dispersion, seen under the latter conditions in graphene, can also be obtained in non-relativistic electron gases by coupling between 2D and 3D electronic systems. As a well investigated example, the acoustic surface plasmons in Shockley surface states, coupled with the bulk electronic system, are discussed. Also the introduction of anisotropy, e.g. by regular arrays of steps, seems to result in linearization (and to partial localization of the plasmons normal to the steps, depending on wavelengths). In quasi-one dimensional (1D) systems, such as arrays of gold chains on regularly stepped Si surfaces, only the dispersion is 1D, whereas shape and slope of the dispersion curves depend on the 2D distribution of charge within each terrace and on coupling between wires on different terraces. In other words, the form of the confining quasi-1D potential enters directly into the 1D plasmon dispersion and gives new opportunities for tuning.

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Section: Systemmentioning

confidence: 86%

Plasmons in one and two dimensions

Pfnür¹,

Tegenkamp²,

Vattuone³

2017

Preprint

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“…Momentum-resolved electron-energy-loss spectroscopy used in their experiments revealed multiple "acoustic" surface plasmons. These authors accounted for this occurrence of low-frequency plasma modes as arising from both the graphene overlayer and the Cu(111) substrate If we follow the paper of Ahn, et al 54 and treat the Cu(111) substrate as a 2DEG, this means that we may adopt our model as follows. There is a graphene overlayer with vacuum on one side and a semi-infinite dielectric with constant b on the other.…”

Section: Plasmon Excitations For a Graphene-2deg Double Layermentioning

confidence: 99%

“…All of this is incumbent on the appearance of the 2D Fourier transform of the Coulomb interaction as 2πe 2 /(4π 0 q ) which appears naturally in the procedure used for calculating the surface response function. In the paper of Ahn, et al 54 , a screening parameter is introduced into the 2D Fourier transform of the Coulomb potential, which has no place in our calculations.…”

Section: Plasmon Excitations For a Graphene-2deg Double Layermentioning

confidence: 99%

Effect of strain on plasmons, screening, and energy loss in graphene/substrate contacts

2018

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The combined effect due to mechanical strain, coupling to the plasmons in a doped conducting substrate, the plasmon-phonon coupling in conjunction with the role played by encapsulation of a secondary two-dimensional (2D) layer is investigated both theoretically and numerically. The calculations are based on the random-phase approximation (RPA) for the surface response function which yields the plasmon dispersion equation that is applicable in the presence or absence of an applied uniaxial strain. We present results showing the dependence of the frequency of the charge density oscillations on the strain modulus and direction of the wave vector in the Brillouin zone.The shielding of a dilute distribution of charges as well as the rate of loss of energy for impinging charges is investigated for this hybrid layered structure.

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