Sharp resonant phonons in two adsorbed slabs

Akjouj, Abdellatif; Boudouti, El Houssaine El; Djafari‐Rouhani, Bahram

doi:10.1016/0038-1098(95)00735-0

Cited by 7 publications

(3 citation statements)

References 25 publications

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“…Note also the measured time delay of a photon tunnelling through a one-dimensional photonic band material [21]. Let us mention, finally, that similar results to those presented here are found by some authors for transverse [22] and sagittal [23] elastic waves in an adsorbed bilayer on a substrate.…”

Section: Discussion and Summarysupporting

confidence: 88%

Resonant states in quantum wells: theoretical analysis of the density of states and phase times

Hammouchi

Boudouti

Nougaoui

et al. 1998

J. Phys.: Condens. Matter

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The existence of sharp resonant states in a single quantum well separated from its semi-infinite substrate by a barrier layer is reported here. These resonances appear as well defined peaks in the density of states. The local and total densities of states are obtained from an analytical determination of the Green functions. The expressions of the transmission and reflection phase times are also derived and compared to the density of states. The positions of the peaks in the density of states enable us to study the energy levels of resonant states as a function of the thicknesses of the barrier and well layers. Specific applications of our analytical results are given in this paper for a bilayer sandwiched between two semi-infinite GaAs and media.

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Section: Discussion and Summarysupporting

confidence: 88%

Resonant states in quantum wells: theoretical analysis of the density of states and phase times

Hammouchi

Boudouti

Nougaoui

et al. 1998

J. Phys.: Condens. Matter

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“…Similar illustrations were presented for pure shear horizontal ͑SH͒ waves in a very recent paper. 27 In the case of sagittal acoustic waves studied here, we show that guided longitudinal acoustic waves with velocities lying in the range of longitudinal velocities of sound may be confined in the topmost layer. Figure 2 gives an illustration of the dispersion curves ͑ve- locity C versus the reduced parallel wave vector k ʈ d 2 ).…”

Section: Numerical Resultsmentioning

confidence: 60%

“…This phenomenon results from the fact that some of the slab modes of the top layer, even if they are in resonance with the substrate bulk modes, cannot propagate in the intermediate layer and therefore remain well-defined guided waves of the higher slab. A preliminary report of these results 26 as well as the results associated with the simplest case of transverse polarization 27 were presented elsewhere. After a brief presentation of the model in Sec.…”

Section: Introductionmentioning

confidence: 97%

Resonant guided elastic waves in an adsorbed bilayer: Theoretical analysis of the density of states

1997

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We study resonant acoustic waves of sagittal polarization in a bilayer deposited on a substrate. Such resonances were initially studied by Brillouin light scattering in a buffer silica layer of a Si-SiO 2 bilayer on a Si substrate. Using a Green's-function method, we have obtained the local and total densities of states as a function of the frequency and the wave vector k ʈ parallel to the interfaces. When the velocities of sound in the buffer layer are higher than those in the topmost layer the former acts as a barrier between phonons of the topmost layer and those of the substrate; therefore well-confined resonant waves may exist in the higher slab, which appear as well-defined peaks in the density of states. The positions of these peaks enable us to study the speed of resonant modes as a function of the parallel wave vector and the thicknesses of the buffer and topmost layers. Specific applications of our analytical results are given in this paper for a GaAs-Si bilayer on a GaAs substrate.

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