Electronic Structures and Seebeck Coefficients of Bi2Te3, Sb2Te3, and (Bi0.25Sb0.75)2Te3: A First-Principles Calculation Study

The electronic structures and Seebeck coefficients of Bi2Te3, Sb2Te3, and (Bi0.25Sb0.75)(2)Te-3 were investigated using a first-principles density-functional-theory approach. The band structures and band gaps of the compounds were obtained and compared with previous experimental results and calculations from the literature to support the accuracy of the calculations. The random mixing of Bi and Sb in the crystal lattices of (Bi0.25Sb0.75)(2)Te-3 was expected from the results of the total energy and the density of states, in accordance with experimental evidence. The Seebeck coefficients of the compounds were estimated from the electronic structures via the Boltzmann transport equation, and were in good agreement with the experimental values. Thus, our results show that the Seebeck coefficients can be utilized to quantitatively identify differences in the density of states.