Details

Autor(en) / Beteiligte

• Music, Denis
• Geyer, Richard W.
• Hans, Marcus

Titel

High-throughput exploration of thermoelectric and mechanical properties of amorphous NbO2 with transition metal additions

Ist Teil von

• Journal of applied physics, 2016-07, Vol.120 (4)

Ort / Verlag

Melville: American Institute of Physics

Erscheinungsjahr

2016

Quelle

American Institute of Physics (AIP) Journals

Beschreibungen/Notizen

• To increase the thermoelectric efficiency and reduce the thermal fatigue upon cyclic heat loading, alloying of amorphous NbO2 with all 3d and 5d transition metals has systematically been investigated using density functional theory. It was found that Ta fulfills the key design criteria, namely, enhancement of the Seebeck coefficient and positive Cauchy pressure (ductility gauge). These quantum mechanical predictions were validated by assessing the thermoelectric and elastic properties on combinatorial thin films, which is a high-throughput approach. The maximum power factor is 2813 μW m−1 K−2 for the Ta/Nb ratio of 0.25, which is a hundredfold increment compared to pure NbO2 and exceeds many oxide thermoelectrics. Based on the elasticity measurements, the consistency between theory and experiment for the Cauchy pressure was attained within 2%. On the basis of the electronic structure analysis, these configurations can be perceived as metallic, which is consistent with low electrical resistivity and ductile behavior. Furthermore, a pronounced quantum confinement effect occurs, which is identified as the physical origin for the Seebeck coefficient enhancement.