在本篇論文中，我們以Al助熔劑長晶法製備單晶結構的三元化合物BaFe2Al9、BaCo2Al9、SrCo2Al9，並利用XRD鑑定其晶體結構，所有樣品結構皆為hexagonal BaFe2Al9-type。為了研究其熱電傳輸特性，我們量測了此系列合金之電阻率(?)、熱傳導率(?)、熱電係數(Ｓ)以及比熱(Cp)。所有BaFe2Al9的熱電量測在100 K左右展現了屬於一階相變(first-order transition)類型的特徵，這表明觀察到的相變與電子的特性變化密切相關。由電阻率量測結果，發現此系列樣品之電阻率皆隨溫度增加，顯示出BaFe2Al9、BaCo2Al9及SrCo2Al9表現皆為普通金屬。藉由熱傳導率量測發現BaFe2Al9單晶的熱導率主要由晶格熱導率(κ_L)所貢獻，而BaCo2Al9、SrCo2Al9單晶的熱導率主要由電子熱導率(κ_e)所貢獻。由熱電係數的實驗數據擬合之斜率帶入莫特定則公式，估算出BaFe2Al9之費米能量約為6.42 (eV)、BaCo2Al9之費米能量約為0.81 (eV)、SrCo2Al9之費米能量約為0.99 (eV)。

Single crystals of the ternary compounds BaFe2Al9, BaCo2Al9 and SrCo2Al9 have been successfully grown by Al self-flux method, and their hexagonal structures have been identified by the x-ray diffraction. We measure the temperature-dependent electric conductivity, thermal conductivity, Seebeck coefficient, and specific heat capacity. BaFe2Al9 exhibits a first-order phase transition at around 100 K, giving evidence that the observed phase transition is strongly associated with the change of the electronic characteristics. The resistivity of this series of samples all increased with temperature, showing that BaFe2Al9, BaCo2Al9, and SrCo2Al9 all behave as ordinary metals. The thermal conductivity of BaFe2Al9 is mainly contributed by lattice thermal conductivity (κ_L), while the thermal conductivity of BaCo2Al9 and SrCo2Al9 is mainly contributed by electron (κ_e). From the fitting slope of the Seebeck coefficient into Mott rule, it is estimated that the Fermi level of BaFe2Al9 is about 6.42 (eV), BaCo2Al9 is about 0.81 (eV), and SrCo2Al9 is about 0.99 (eV).

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