Size dependence of the local structure and atomic correlations in tellurium nanoparticles

Only a few studies have been carried out on nanoparticles of materials having a hierarchic structure, contrary to nanoparticles of metals or tetrahedrally bonded semiconductor materials. Tellurium (Te) is the representative of the elements that have a hierarchic structure, that is, the covalently bonded chains and the interchain interactions between the chains. In this paper, the structure of Te nanoparticles was studied with varying nanoparticle size. While the covalently bonded 2-fold chain structure is preserved, the intrachain first nearest neighbor (1NN) atomic distance (r _intra) shortens, and the interchain 1NN coordination number (N _inter) decreases with decreasing nanoparticle size; they have strong correlation with each other. The correlation suggests not only that piling up of the primary structure makes the secondary structure but also that the secondary structure affects the primary structure. The present results are distinguishing phenomena of the hierarchic elements such as tellurium.