Phonon transmission via a three–terminal junction in low dimensional wave-guides

¹ Département de Physique, Faculté des Sciences, Université Mouloud Mammeri de Tizi-Ouzou, 15000 Tizi-Ouzou, Algeria
² Laboratoire PEC, Université du Maine, 72085 Le Mans, France
³ Department of Physics, McGill University, 3600 rue University, Montreal, QC Canada H3A 2T8
⁴ Laboratoire d'Acoustique, Université du Maine, 72085 Le Mans, France
⁵ Institut de Théorie des Phénomènes Physiques, EPFL, 1015 Lausanne, Switzerland

Corresponding authors: mehand.belhadi@yahoo.com antoine.khater@univ-lemans.fr

Received: 18 November 2005
Revised: 5 June 2006
Accepted: 9 June 2006
Published online: 23 August 2006

Abstract

Coherent phonon scattering and transmission via a three-terminal junction in low-dimensional structures is investigated. The model system consists of two-dimensional crystalline wave-guides, constructed of double atomic chains that are joined together by a nanostructured T-shaped junction. The matching method theoretical approach is used to study the dynamics of the system. A calculation is presented for the coherent reflection and transmission scattering probabilities of the system phonons, as elements of a Landauer type scattering matrix. The scattering and transmission spectra via the T-shaped junction are analyzed as a function of the incident frequency per propagating mode of the perfect wave-guides. Our results show that the junction is an effective phonon splitter and suggest that its characteristics may be controlled by varying its nanometric parameters. Asymmetric Fano-like resonances are observed in the spectra which result from the coherent coupling between the localized modes of the T-shaped junction and the propagating modes of the wave-guides.