From band structure to thermoelectric Efficiency: A first-principles study of K2ZrTe3 and Rb2ZrTe3

초록

A comprehensive first-principles investigation of the structural, electronic, optical, and thermoelectric properties of the zirconium-based telluride chalcogenides K2ZrTe3 and Rb2ZrTe3 is presented using density functional theory. Both compounds crystallize in a monoclinic P2(1)/c structure and are found to be thermodynamically stable by calculating the formation energy and phonon dispersion. Electronic band-structure calculations using the TB-mBJ potential reveal indirect semiconducting band gaps of 0.506eV and 0.557eV, respectively. The valence bands are dominated by Te-p states, while Zr-d states mainly contribute to the conduction bands, leading to moderate electron effective masses (0.42-0.46 m(0)) and heavier hole masses (0.95-0.98 m(0)). Optical calculations indicate strong absorption, large refractive indices, and pronounced extinction and reflectivity features in the ultraviolet region. Thermoelectric analysis predicts high Seebeck coefficients (similar to 200 mu V/K) and estimated ZT values (electronic contribution) indicate promising thermoelectric performance for K2ZrTe3 at elevated temperatures, highlighting its potential for energy-conversion applications.

키워드