High-Pressure Incommensurate Structures in Nanomaterials

Nanomaterials(NMs) have been shown to possess different properties compared to their extended solids. Recently, a high-pressure study of Te (Tellurium) nano-cylinders has revealed compressibility effects that are different to those observed in bulk-Te and phase-transition pressures were strongly size dependent. Unfortunately, the incommensurate structure of Te, which has been found in bulk material, was not reported. Bismuth(Bi) bulk material has also been disclosed to exhibit incommensurate host-guest structure (Bi-III) at high pressure. To investigate incommensurate structure in NMs, the synthesised-Bi nanoparticles from thermal-decomposition method were studied using high-pressure powder x-ray diffraction technique.

In this talk, I will present the Bi-nanoparticles synthesis process and also the nanoparticles structural study by x-ray diffraction. I find that the incommensurate phase does exist in nano-Bi with phase transition pressures that are somewhat different to those observed in the bulk material. Moreover, Rietveld analysis of the diffraction profiles is being used to determine the further details of the structure. The results of this analysis will be presented.