Interfacial disconnections at Sb₂Te₃ precipitates in PbTe: Mechanisms of strain accommodation and phase transformation at a tetradymite/rocksalt telluride interface

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• 作者：N.A.  ; Heinz^a ; T.  ; Ikeda^a ; G.J.  ; Snyder^a ; D.L.  ; Medlin^b ;   ; ^{dlmedli@sandia.gov}
• 关键词：Interface structure ; Phase transformations ; Dislocations ; High-resolution transmission electron microscopy (HRTEM) ; Thermoelectric materials
• 刊名：Acta Materialia
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：59
• 期：20
• 页码：7724-7735
• 全文大小：2238 K

文摘

Understanding the structure and formation mechanisms of interfaces between different telluride phases is important to the development of thermoelectric nanocomposites. Here, we investigate the interfacial structure of tetradymite precipitates in a rocksalt telluride matrix, focusing in particular on precipitates of Sb₂Te₃ in PbTe. Using high-resolution transmission electron microscopy, we investigate the structure and arrangement of interfacial disconnections¡ªi.e. interfacial steps possessing dislocation character¡ªobserved in this system. Our analyses provide insight concerning the roles of these defects in accommodating the large interfacial misfit (6.7 % ) in this system and in mediating the transformation from the rocksalt to the tetradymite structure. Our observations also suggest how such interfacial disconnections could arise through the dissociation of crystal lattice dislocations that accommodate the misfit on initially flat segments of the interface.