Phonon scattering via an atomic well in free standing thin solid films

A. Khater, M. Belhadi

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

A theoretical model is presented for the study of the scattering of phonons at an extended inhomogeneous boundary separating thin solid monatomic films. The model system consists of two solid films with otherwise stress-free surfaces on either side of an atomic well boundary. The coherent reflection and transmission scattering cross sections for phonons incident from the interior of the thin films on the inhomogeneous atomic well boundary are calculated in accordance with the Landauer-Büttiker coherent scattering description, using the matching method with nearest and next-nearest neighbor elastic force constants. This is done specifically for two different cases of elastic interactions on the boundary to investigate the consequences of their softening and hardening for the coherently scattered spectra. The numerical results yield an understanding for the effects on coherent phonon conductance due to phonon incidence and to the elastic nature of the boundary. The coherent reflection and transmission scattering cross sections show characteristic spectral features that are invariant with the change of the boundary force constants, depending solely on the cutoff frequencies for the propagating phonons and on incidence angle. They also show the Fano resonances that result from the interactions of propagating phonons with the localized vibrational Rayleigh-like modes on the boundary, depending on the boundary elastic force constants. The evolution of the system average conductance per phonon mode with incidence illustrates an interesting effect. An experimental observable this average conductance remains constant at half a phonon in intensity over significant frequency intervals. The effect is remarkable inasmuch as it permits in principle the possibility of a constant intensity phonon source.

Original languageEnglish
Pages (from-to)271-280
Number of pages10
JournalSurface Review and Letters
Volume16
Issue number2
DOIs
Publication statusPublished - Apr 2009
Externally publishedYes

Fingerprint

Phonon scattering
Phonons
Scattering
scattering
phonons
Coherent scattering
incidence
Cutoff frequency
scattering cross sections
Hardening
Thin films
coherent scattering
hardening
softening
cut-off
interactions
intervals
thin films

Keywords

  • Localized modes
  • Phonons in low-dimensional nanoscale materials
  • Surface and interface dynamics

ASJC Scopus subject areas

  • Surfaces and Interfaces
  • Condensed Matter Physics
  • Materials Chemistry
  • Surfaces, Coatings and Films

Cite this

Phonon scattering via an atomic well in free standing thin solid films. / Khater, A.; Belhadi, M.

In: Surface Review and Letters, Vol. 16, No. 2, 04.2009, p. 271-280.

Research output: Contribution to journalArticle

Khater, A. ; Belhadi, M. / Phonon scattering via an atomic well in free standing thin solid films. In: Surface Review and Letters. 2009 ; Vol. 16, No. 2. pp. 271-280.
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