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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Estimating carrier relaxation times in the Ba8Ga16Ge30 clathrate in the extrinsic regime

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Gonzalez-Romero, Robert L. ; Antonelli, A.
Total Authors: 2
Document type: Journal article
Source: Physical Chemistry Chemical Physics; v. 19, n. 4, p. 3010-3018, 2017.
Web of Science Citations: 5

We used a semi-empirical method to extract carrier relaxation times at different temperatures (tau(T)) in thermoelectric materials from a combination of experimental results and first-principles calculations. The methodology is based on the Boltzmann transport equation formalism within the relaxation time approximation. It can be applied to single crystals and polycrystalline materials. We applied the method to investigate the electronic transport properties of the clathrate compound Ba8Ga16Ge30 type-I. The calculations indicate that the carrier relaxation process in single crystals is dominated by electron-phonon scattering (tau proportional to T-3/2), while in polycrystalline materials scattering at grain boundaries dominates (tau similar to cte). The Seebeck coefficient, electrical conductivity, and electron heat conduction are in consistent agreement with experiment. Furthermore, the Slack relation for lattice heat conductivity was successfully applied to the material. The calculated figure of merit is in good agreement with experimental results. (AU)

FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
Grantee:Munir Salomao Skaf
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 13/14065-7 - A first-principles study of electronic, structural, and transport properties of clathrates for thermoelectric applications
Grantee:Robert Luis González Romero
Support type: Scholarships in Brazil - Post-Doctorate