Department of Chemistry and iNano, Aarhus University Aarhus, 8000, Denmark
Jonas Beyer
Department of Chemistry and iNano, Aarhus University Aarhus, 8000, Denmark
Karl F. F. Fischer
Department of Chemistry and iNano, Aarhus University Aarhus, 8000, Denmark
Kaiyang Xia
State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
Tiejun Zhu
State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
Bo B. Iversen
Department of Chemistry and iNano, Aarhus University Aarhus, 8000, Denmark
Although crystalline solids are characterized by their periodic structures, some are only periodic on average and deviate on a local scale. Such disordered crystals with distinct local structures have unique properties arising from both collective and localized behaviour. Different local orderings can exist with identical average structures, making their differences hidden to Bragg diffraction methods. Using high-quality single-crystal X-ray diffuse scattering the local order in thermoelectric half-Heusler Nb1−xCoSb is investigated, for which different local orderings are observed. It is shown that the vacancy distribution follows a vacancy repulsion model and the crystal composition is found always to be close to x = 1/6 irrespective of nominal sample composition. However, the specific synthesis method controls the local order and thereby the thermoelectric properties thus providing a new frontier for tuning material properties.
