Reactions of alkaline earth (AE) elements with silicon in Mg/Al flux mixtures has yielded a large family of compounds with complex structures and a charge-balanced 2:1 ratio of alkaline earth cations to silicon anions. This family of (AE/Mg)2Si silicides can be classified as Zintl phases, as they are salt-like compounds that form when highly-electropositive alkaline earth/rare earth elements (Ca, Sr, Ba, Eu, Yb) react with main group metalloids. As a result of being charge-balanced, these compounds are semimetals. This feature, along with their complex structures and incorporation of heavy elements, indicate that these compounds have the potential for thermoelectric and magnetic applications. While Mg/Al flux reactions are highly productive, the products tend to incorporate trace amounts of aluminum which may affect the resulting properties. To avoid this, the use of magnesium/zinc flux is being studied in the synthesis of these (AE/Mg)2Si Zintl phases, and the resulting magnetic, transport and thermoelectric properties of the products are measured. Comparison of similar materials grown from Mg/Al flux allows us to study the effects of incorporation of aluminum into the resulting product compared to the product without aluminum incorporation.

Growth of semimetallic silicides from Mg/Al and Mg/Zn flux reactions

ACS Spring Meeting 2021

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