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  • 02월 19일 10시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제121회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Rare-Earth Metals Doped Complex Zintl Phase Thermoelectric Materials: Ca11-xRExSb10-y System

2018년 2월 7일 14시 21분 06초
INOR.P-154 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
4월 19일 (목요일) 11:00~12:30
Inorganic Chemistry
저자 및
JunSu Lee, Tae-Soo You*
Department of Chemistry, Chungbuk Natioanl University, Korea

In our previous articles, we reported two series of complex Zintl phase thermoelectric materials adopting the Ho11Ge10-type structures: Ca11-xYbxSb10-yGez (0 ≤ x ≤ 9; 0 ≤ y ≤ 3; 0 ≤ z ≤ 3) and Eu11-xKxBi10-ySny (x = 0, 0.26; y = 0.86, 1.93) systems. In these investigations, we have tried to apply the p-type single or double doping for the anionic or cationic elements. However, since there was no attempt to apply the n-type doping for this Ho11Ge10-type phase, we planned to introduce n-type dopant using rare-earth metals for the binary Ca11Sb10. Four novel ternary Zintl phase compounds forming the ternary Ca11-xRExSb10-y (RE = La, Ce, Nd, Sm; 0.18(4) ≤ x ≤ 0.42(2), 0.14(1) ≤ y ≤ 0.41(1)) system were successfully synthesized by arc-melting, and their crystal structures were characterized by both PXRD and SXRD analyses. Given that we used the n-type dopants, we originally expected to provide more than 72 valence electrons (ve-) for the title system. However, due to the non-neglectable Sb deficiencies found at the Sb3 site (Wyckoff 8h), the total number of valence electrons ranges only between 70.37 in Ca10.58(2)La0.42Sb9.59(1) and 71.48 in Ca10.82(4)Sm0.18Sb9.86(1), both of which were less than 72 ve-. To understand this observed Sb deficiencies, a series of theoretical calculations using tight-binding linear muffin-tin orbital (TB-LMTO) method were performed. Eventually we reveal that the nature finds its own way to stabilize the given crystal structure by allowing a certain amount of vacancies at the Sb3 site (Wyckoff 8h) in the title compounds.