Heat transfer by metallic thin film sandwiched in semiconductor lattice

Abstract

We calculate, theoretically, the coherent phonons transmission and the thermal transfer through sandwiched metallic thin films in semiconductor lattices. The model system consists of a finite thickness of an ultrathin metallic film joining two semi-infinite semiconductor leads. The heterostructure dynamics is analyzed by using the equations of motion for the atomic displacements on the lattice sites, valid for the different temperatures of interest. Phonons transmission and reflection via interface boundary are calculated for the studied semiconductor lattice by employing the matching method. The results are presented for all accessible frequencies in the propagating bands, at variable temperatures and at a given directions of phonons incidence on the boundary. The considered model is applied, in particular, to the Si/Al/Si heterostructure. We note that the interfacial region of the system affects the vibration spectra and the phonon transmittance and modifies its thermal conductivity. This elucidates how the heat transfer depends on the elastic waves transmission according to the spatially disposition of the atomic layers of the heterostructures.