Influence of grain size distribution on the lattice thermal conductivity of Bi2Te3-Sb2Te3-based nanostructured materials

Abstract

The change of the lattice thermal conductivity of bulk nanostructured materials based on Bi2Te3-Sb2Te3 solid solutions with grain size distribution has been studied. These materials have a polycrystalline structure with grain sizes ranging from a few tens of a nanometer to a few micrometers. Large grains may contain inclusions or consist of several smaller parts which can be identified with coherent scattering regions seen in X-ray diffraction. The change of the lattice thermal conductivity mediated by additional scattering by inclusions and grain boundaries has been calculated. This calculation allows for the effect of nanoparticle size distribution. The calculated estimates are compared with the available experimental data.