Triple phase structure and electron density analysis of the thermoelectric material Bi80Sb20

The thermoelectric material Bi80Sb20 was grown by high temperature melt–quench growth method and characterized by powder XRD. The Rietveld refinements revealed the presence of Bi80Sb20 and also the elemental parents Bi and Sb. All the three phases were analyzed and the electron density distribution and local structure of Bi, Sb and Bi80Sb20 were individually studied. The bonding between the atoms was studied using maximum entropy method (MEM). A comparison of 3D and 2D electron density distributions of Bi, Sb and Bi80Sb20 on the (110) and (024) planes clearly shows highly concentrated and localized electron clouds in Bi80Sb20 supporting the use of BiSb alloy as a thermoelectric material.

The electron density distribution and bonding in Bi80Sb20 were analyzed using X-ray powder data sets. The correlation of thermoelectric properties with the structure is made. The powder X-ray data of Bi80Sb20 system was refined and the three phases present in the data were resolved. The compositions of these three phases (Bi80Sb20, Bi, and Sb) are found to be 83.91%, 13.07% and 3.02% respectively.Figure optionsDownload as PowerPoint slide