Thermoelectric transport properties (Seebeck coefficient, S, and electrical conductivity, σ) of p -type Bi and Sb tellurides are investigated using a first-principles all-electron density-functional approach. We demonstrate that the carrier concentration, band gap, and lattice constants have an important influence on the temperature behavior of S and that the volume expansion by 5.5% in Sb2Te3 results in an increase in S by 33μV/K at 300 K. We argue that in addition to the electronic structure characteristics, the volume also affects the value of S and hence should be considered as an origin of the experimental observations that S can be enhanced by doping Sb2Te3 with Bi (which has a larger ionic size) in Sb sites or by the deposition of thick Bi2Te3 layers alternating with thinner Sb2Te3 layers in a superlattice, Bi2Te3/ Sb2Te3. We show that the optimal carrier concentration for the best power factor of Bi2Te3 and Sb2 Te3 is approximately 1019 cm-3
M. Park et al., "Electronic Structure and Volume Effect on Thermoelectric Transport in P -Type Bi and Sb Tellurides," Physical review B: Condensed matter and materials physics, vol. 81, no. 15, pp. 155211-1 - 155211-5, American Physical Society (APS), Apr 2010.
The definitive version is available at https://doi.org/10.1103/PhysRevB.81.155211
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01 Apr 2010