ANALYSIS OF THE CRYSTAL LATTICE AND BAND STRUCTURE OF BI₂TE₃ AS A MATERIAL FOR THERMOELECTRIC AND SPINTRONIC DEVICES

This study presents a comprehensive theoretical and experimental examination of the atomic bonding nature and electronic structure of bismuth telluride (Bi₂Te₃), a well-known layered thermoelectric semiconductor. Particular attention is given to its trigonal crystal symmetry, the role of spin-orbit interactions in shaping its band topology, and the significance of weak Van der Waals forces between layers. The bonding types between Bi and Te atoms are thoroughly analyzed using the frameworks of Mooser-Pearson, Lagrenaudie, and Drabble-Goodman. It is shown that structural changes, especially at 60° twin boundaries, can significantly modify the local electronic states and, consequently, the material’s transport and optical performance. These insights may inform the design of advanced thermoelectric and spintronic devices based on Bi₂Te₃.