First principles calculations on the thermoelectric properties of bulk Au2S with ultra-low lattice thermal conductivity

Y Y Wu; X L Zhu; H Y Yang; Z G Wang; Y H Li; B T Wang

doi:10.1088/1674-1056/ab973c

Journals >Chinese Physics B >Volume 29 >Issue 8 >Page > Article

Chinese Physics B
Vol. 29, Issue 8, (2020)

First principles calculations on the thermoelectric properties of bulk Au₂S with ultra-low lattice thermal conductivity

Y Y Wu^1、2、3, X L Zhu^2、3, H Y Yang⁴, Z G Wang⁵, Y H Li^1、†, and B T Wang^2、3、6

Author Affiliations

¹School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China

²Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China

³Spallation Neutron Source Science Center, Dongguan 52808, China

⁴School of Materials Science and Engineering, Hunan University of Science and Technology, Xiangtan 11201, China

⁵Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China

⁶Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 03000, China

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DOI: 10.1088/1674-1056/ab973c Cite this Article

Y Y Wu, X L Zhu, H Y Yang, Z G Wang, Y H Li, B T Wang. First principles calculations on the thermoelectric properties of bulk Au₂S with ultra-low lattice thermal conductivity[J]. Chinese Physics B, 2020, 29(8): Copy Citation Text

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Abstract

Sulfide nanocrystals and their composites have shown great potential in the thermoelectric (TE) field due to their extremely low thermal conductivity. Recently a solid and hollow metastable Au2S nanocrystalline has been successfully synthesized. Herein, we study the TE properties of this bulk Au2S by first-principles calculations and semiclassical Boltzmann transport theory, which provides the basis for its further experimental studies. Our results indicate that the highly twofold degeneracy of the bands appears at the Γ point in the Brillouin zone, resulting in a high Seebeck coefficient. Besides, Au2S exhibits an ultra-low lattice thermal conductivity (～ 0.88 W?m-1?K-1 at 700 K). At 700 K, the thermoelectric figure of merit of the optimal p-type doping is close to 1.76, which is higher than 0.8 of ZrSb at 700 K and 1.4 of PtTe at 750 K. Our work clearly demonstrates the advantages of Au2S as a TE material and would greatly inspire further experimental studies and verifications.

Keywords

first principles calculation thermodynamic transport properties

$$ \begin{eqnarray}\begin{array}{lll}{S}_{\alpha \beta }(T,\mu ) & = & \displaystyle \frac{1}{eTV{\sigma }_{\alpha \beta }(T,\mu )}\displaystyle \int {\Sigma }_{\alpha \beta }(\varepsilon )(\varepsilon -\mu )\\ & & \times \left[-\displaystyle \frac{\partial {f}_{\mu }(T,\varepsilon )}{\partial \varepsilon }\right]{\rm{d}}\varepsilon,\end{array}\end{eqnarray}$$

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$$ \begin{eqnarray}{\sigma }_{\alpha \beta }(T,\mu )=\displaystyle \frac{1}{V}\displaystyle \int {\Sigma }_{\alpha \beta }(\varepsilon )\left[-\displaystyle \frac{\partial {f}_{\mu }(T,\varepsilon )}{\partial \varepsilon }\right]{\rm{d}}\varepsilon,\end{eqnarray}$$

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$$ \begin{eqnarray}{\Sigma }_{\alpha \beta }(\varepsilon )=\displaystyle \frac{{e}^{2}}{{N}_{0}}\displaystyle {\sum }_{i,q}{\tau }_{{\rm{e}}}{\upsilon }_{\alpha }(i,q){\upsilon }_{\beta }(i,q)\displaystyle \frac{\delta (\varepsilon -{\varepsilon }_{i,q})}{d\varepsilon },\end{eqnarray}$$

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$$ \begin{eqnarray}S=\displaystyle \frac{{\pi }^{2}{k}_{{\rm{B}}}^{2}T}{3e}{\left\{\displaystyle \frac{1}{n}\displaystyle \frac{{\rm{d}}n(\varepsilon )}{{\rm{d}}\varepsilon }+\displaystyle \frac{1}{{\mu }_{{\rm{m}}}}\displaystyle \frac{{\rm{d}}{\mu }_{{\rm{m}}}(\varepsilon )}{{\rm{d}}\varepsilon }\right\}}_{\varepsilon =\mu },\end{eqnarray}$$

(4)

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