Atomic-Scale Interfacial Structure in Rock Salt and Tetradymite Chalcogenide Thermoelectric Materials

Abstract

Interfaces play important roles in the performance of nanostructured thermoelectric materials. However, our understanding of the atomic-scale structure of these interfaces is only beginning to emerge. In this overview article, we highlight and review several examples illustrating aspects of interfacial structure in the rock salt and tetradymite classes of chalcogenide materials. The chalcogenide compounds encompass some of the most successful and well-understood thermoelectric materials employed in actual application and are also relevant more broadly in diverse fields including phase-change memory materials, infrared radiation detection, and topological insulators. The examples we consider here focus in three areas: the influence of weak interlayer bonding on grain boundary structure in Bi_(2)Te_3, crystallographic alignment and interfacial coherency in rock salt and related cubic chalcogenides, and the structure of interfaces at tetradymite precipitates in a rock salt chalcogenide matrix. The complex interfaces in these systems can be understood and generalized by considering the similarities between the rock salt, tetradymite, and related structures and by analyzing of the relevant interfacial defects.

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