Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5496652 | Physics Letters A | 2017 | 7 Pages |
Abstract
Based on first-principles calculations we systematically studied the electronic structure and thermoelectric properties of Zr1 â xHfxNiPb (x = 0, 0.25, 0.5, 0.75, 1) compounds with TB-mBJ and TB-mBJ plus spin-orbit coupling methods. Our results indicate that these compounds are thermodynamic stabled narrow-gap semiconductors. The low frequency optical branches intersect with the acoustic modes below 75cmâ1 for these artificial compounds, which enhance the phonon scattering and then decrease thermal conductivity. The Hf substitution significantly decreases the lattice thermal conductivity from 13.1Wmâ1Kâ1 (x = 0) to 0.23Wmâ1Kâ1 (x = 0.25) at 300 K. We confirmed that the Hf doping hardly influences the power factors S2TÏ in both of p- and n-type, but greatly decreases the thermal conductivity κ, i.e. improving the figure of merit ZT=S2TÏ/κ. The Zr0.75Hf0.25NiPb, Zr0.5Hf0.5NiPb and Zr0.25Hf0.75NiPb, with ultra low thermal conductivity (0.23, 2.2 and 0.48Wmâ1Kâ1 at 300 K) and higher power factor, may become new candidates of high performance thermoelectric materials in both of p- and n-type.
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Authors
Dongyang Wang, Guangtao Wang,