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Impact of the scattering physics on the power factor of complex thermoelectric materials
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Graziosi, Patrizio, Kumarasinghe, Chathurangi and Neophytou, Neophytos (2019) Impact of the scattering physics on the power factor of complex thermoelectric materials. Journal of Applied Physics, 126 (15). 155701. doi:10.1063/1.5116793 ISSN 0021-8979.
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WRAP-impact-scattering-physics-power-factor-complex-materials-Neophytou-2019.pdf - Accepted Version - Requires a PDF viewer. Download (2338Kb) | Preview |
Official URL: http://dx.doi.org/10.1063/1.5116793
Abstract
We assess the impact of the scattering physics assumptions on the thermoelectric properties of five Co-based p-type half-Heusler alloys by considering full energy-dependent scattering times vs the commonly employed constant scattering time. For this, we employ density functional theory band structures and a full numerical scheme that uses Fermi's golden rule to extract the momentum relaxation times of each state at every energy, momentum, and band. We consider electron-phonon scattering (acoustic and optical), as well as ionized impurity scattering, and evaluate the qualitative and quantitative differences in the power factors of the materials compared to the case where the constant scattering time is employed. We show that the thermoelectric power factors extracted from the two different methods differ in terms of (i) their ranking between materials, (ii) the carrier density where the peak power factor appears, and (iii) their trends with temperature. We further show that the constant relaxation time approximation smoothens out the richness in the band structure features, thus limiting the possibilities of exploring this richness for material design and optimization. These details are more properly captured under full energy/momentum-dependent scattering time considerations. Finally, by mapping the conductivities extracted within the two schemes, we provide appropriate density-dependent constant relaxation times that could be employed as a fast first-order approximation for extracting charge transport properties in the half-Heuslers we consider.
Item Type: | Journal Article | |||||||||
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Subjects: | Q Science > QC Physics T Technology > TK Electrical engineering. Electronics Nuclear engineering |
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Divisions: | Faculty of Science, Engineering and Medicine > Engineering > Engineering | |||||||||
Library of Congress Subject Headings (LCSH): | Thermoelectricity, Thermoelectric materials, Scattering (Physics) | |||||||||
Journal or Publication Title: | Journal of Applied Physics | |||||||||
Publisher: | American Institute of Physics | |||||||||
ISSN: | 0021-8979 | |||||||||
Official Date: | 16 October 2019 | |||||||||
Dates: |
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Volume: | 126 | |||||||||
Number: | 15 | |||||||||
Article Number: | 155701 | |||||||||
DOI: | 10.1063/1.5116793 | |||||||||
Status: | Peer Reviewed | |||||||||
Publication Status: | Published | |||||||||
Reuse Statement (publisher, data, author rights): | This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. | |||||||||
Access rights to Published version: | Restricted or Subscription Access | |||||||||
Date of first compliant deposit: | 18 October 2019 | |||||||||
Date of first compliant Open Access: | 18 October 2019 | |||||||||
RIOXX Funder/Project Grant: |
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