Anomalously Large Seebeck Coefficient of CuFeS2 Derives from Large Asymmetry in the Energy Dependence of Carrier Relaxation Time

The Seebeck effect in a material originates from the distribution of asymmetry in the electron transport under a temperature gradient, which has contributions from the energy-dependent electronic density-of-states and carrier mobility. However, because the energy dependence of common electron scatte...

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Bibliographic Details
Published in:Chemistry of materials 2020-03, Vol.32 (6), p.2639-2646
Main Authors: Xie, Hongyao, Su, Xianli, Bailey, Trevor P, Zhang, Cheng, Liu, Wei, Uher, Ctirad, Tang, Xinfeng, Kanatzidis, Mercouri G
Format: Article
Language:English
Subjects:
Carrier dynamics
Electrical conductivity
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Mobility
Scattering
Thermodynamic modeling
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Summary:The Seebeck effect in a material originates from the distribution of asymmetry in the electron transport under a temperature gradient, which has contributions from the energy-dependent electronic density-of-states and carrier mobility. However, because the energy dependence of common electron scattering mechanisms is weak, the mobility-driven Seebeck coefficient has long been ignored in most thermoelectric materials, and the energy asymmetry of the density-of-states has been considered the dominant contribution. In this work, we describe a hopping transport behavior observed in CuFeS2, and a large carrier Hall mobility gradient of dμH/dT that creates an unusually large energy-dependent mobility contribution to the Seebeck coefficient. This work offers several ideas regarding the mobility-driven Seebeck effect and its potential utilization in the design of thermoelectric materials.
ISSN:0897-4756
1520-5002
DOI:10.1021/acs.chemmater.0c00388