Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 27: Topical Session: Combinatorial Materials Science III

MM 27.2: Topical Talk

Tuesday, March 12, 2013, 15:30–16:00, H25

Combinatorics of RuO2 based thermoelectrics — •Denis Music, Felix Basse, and Jochen Schneider — Materials Chemistry, RWTH Aachen University, Kopernikusstr. 10, 52074 Aachen, Germany

RuO2 (P42/mnm, rutile) exhibits interesting transport properties, such as low resistivity, as well as large thermal and chemical stability. It is a promising candidate for thermoelectric devices. The quantum mechanically guided design proposal is based on identifying suitable alloying elements for RuO2 to improve the transport properties and phase stability thereof. Using ab initio calculations, we probed all 4d transition metals and identified Nb and Y to be the best choice. Based on this design proposal, Nb and Y alloyed RuO2 thin films were grown by combinatorial reactive sputtering. Nb and Y can be incorporated in the rutile structure. Nanorods were formed and Nb2O5/Y2O3 coordination appears at increased alloying contents. This may be understood based on our ab initio molecular dynamics data. Surface coarsening on the atomic scale occurs due to O crosslinking of two neighboring Nb-O/Y-O units. Hence, it is reasonable to assume that these units contribute towards the experimentally observed formation of nanorods. Further alloying elements and their influence on structure evolution and transport properties will also be discussed.