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Enhanced thermoelectric performance of PbTe within the orthorhombicPnmaphase

Physical Review B2007Vol. 76(15)

Citations Over TimeTop 10% of 2007 papers

Yi Wang, Xin Chen, Tian Cui, Yingli Niu, Yanchao Wang, Mei Wang, Yanming Ma, Guangtian Zou

Abstract

The thermoelectric properties of PbTe within the NaCl (B1) and the orthorhombic $Pnma$ phases are extensively studied by ab initio calculations using the full-potential linearized augmented plane-wave method and the semiclassical Boltzmann theory. The calculations of $n$- and $p$-type Seebeck coefficients for the B1 structure suggested that the energy band gap plays an important role in determining the thermoelectric properties, but only at lower carrier concentrations. We found that the $n$-doped $Pnma$ phase at $6.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ has a larger Seebeck coefficient than that of the $n$-doped B1 phase at zero pressure, but has a comparable electric conductivity. This fact could be well understood by the large density of states in the conduction band and the large anisotropy in the band structure and constant energy surface. Our calculations also predicted that the largest $n$-type ZT values at 300 and $600\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ of the $Pnma$ phase at $6.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$ can reach up to 0.9 and 1.59, respectively, which are two times larger than those in B1 phase at zero pressure. The current theory strongly suggests that the $Pnma$ structure of PbTe is an excellent thermoelectric material. It is desirable to synthesize the $Pnma$ phase of PbTe at ambient pressure by making use of its high performance.

Citations Over TimeTop 10% of 2007 papers

Abstract

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