Phonons transmittance behavior through a stepped nanowire

M. S. Rabia (1)

1 UMMTO - Université Mouloud Mammeri [Tizi Ouzou]

In this work, we study the influence of a reticular defect on the scattering properties of elastic waves. The system model is constituted of a quantum thread composed of an infinite atomic chain, assimilated to a perfect wave guide including geometric shortcomings (walks, terraces, etc.). The mathematical treatment of the problem, based on the Landauer-Büttiker principle, resorts to the matching method in the the harmonic approximation framework. The dynamics of the perfect regions, situated on both sides of the defect, introduced the essential features of the mathematical formalism necessary to the diffusion. Considering the scattering boundary conditions as well as the conditions of symmetry, the equations of motion allows one to establish the dynamical matrix of the perfect lattice. Its resolution generates the eigenmodes of vibration and their corresponding polarizations. In prevention of scatterer, the wave is characterized by attenuation factor that permit to study the functional behaviours of the vibrational modes including both propagating and evanescent modes. The numerical results show that the interferences between multiply reflected waves in the perturbed region let characteristic prints in the transmittance spectra. In other words, the spectra gotten by scattering experiments through a sample contain information on the specific defect structure of the considered system.

Mots clés: Reticular dynamics; Disordered mesoscopic systems; Cistallographic waveguides; Matching Technique

Domaines: Acoustique [physics.class-ph]; Acoustique [physics.class-ph]

M. S. Rabia. Phonons transmittance behavior through a stepped nanowire. 10ème Congrès Français d'Acoustique, Apr 2010, Lyon, France. ⟨hal-00533175⟩