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arXiv 1605.01720cond-mat.str-elcond-mat.mtrl-sci
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掺杂FeSb $_2$块体晶体热电性能的增强

Enhancement of the thermoelectric properties in doped FeSb$_2$ bulk crystals

Kefeng Wang, Rongwei Hu, John Warren, C. Petrovic

摘要:

近藤绝缘体FeSb $_2$具有大的Seebeck系数,如果没有大的热导率$κ$,它将在低温热电应用中具有潜力。本文研究了高质量单晶中Fe和Sb位不同化学取代对热导率和热电效应的影响。在Sb位处Te掺杂的$5\%$处,热导率从未掺杂样品中的$\sim 250$ W/Km抑制到约8 W/Km。然而,在Fe位处的Cr和Co掺杂比Te掺杂更慢地抑制热导率,并且即使在20 $\%$ Cr/Co掺杂下,热导率仍保持$\sim 30$ W/Km。对声子散射的不同贡献的分析表明,碲对$κ$的巨抑制是由于应变场起伏引起的点缺陷散射的增强。相比之下,Te掺杂对相关效应的影响较小,然后对于小的Te取代,仍保持大幅度的塞贝克系数,导致Fe(Sb $_{0.9}$ Te $_{0.1}$)$_2$中的热电优值($\sim 100$ K下的$ZT\sim 0.05$)增强。

英文摘要:

Kondo insulator FeSb$_2$ with large Seebeck coefficient would have potential in thermoelectric applications in cryogenic temperature range if it had not been for large thermal conductivity $κ$. Here we studied the influence of different chemical substitutions at Fe and Sb site on thermal conductivity and thermoelectric effect in high quality single crystals. At $5\%$ of Te doping at Sb site thermal conductivity is suppressed from $\sim 250$ W/Km in undoped sample to about 8 W/Km. However, Cr and Co doping at Fe site suppresses thermal conductivity more slowly than Te doping, and even at 20$\%$ Cr/Co doping the thermal conductivity remains $\sim 30$ W/Km. The analysis of different contributions to phonon scattering indicates that the giant suppression of $κ$ with Te is due to the enhanced point defect scattering originating from the strain field fluctuations. In contrast, Te-doping has small influence on the correlation effects and then for small Te substitution the large magnitude of the Seebeck coefficient is still preserved, leading to the enhanced thermoelectric figure of merit ($ZT\sim 0.05$ at $\sim 100$ K) in Fe(Sb$_{0.9}$Te$_{0.1}$)$_2$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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