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An Extensive Theoretical Study of the Phonon Conductivity and Thermoelectric Properties of SiGe Alloys

Published online by Cambridge University Press:  16 February 2012

Iowerth O. Thomas  and
Gyaneshwar P. Srivastava
Iowerth O. Thomas
Affiliation:
School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
Gyaneshwar P. Srivastava
Affiliation:
School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK
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Abstract

We present an extensive theoretical study of the phonon conductivity and thermoelectric properties of SiGe alloys. Phonon dispersion relations and group velocities – required for conductivity calculations – are obtained by employing the density-functional-perturbation scheme. The cubic anharmonic potential has been expressed by treating the Gr¨uneisen constant as a semi-adjustable mode-averaged parameter. Calculations are also performed, within the nearly-free-electron approximation, for the temperature variation of the Fermi energy, Seebeck coefficient, electrical conductivity, and electronic polar and bipolar contributions to thermal conductivity. Results are compared with experimental measurements for n-doped pressure-sintered Si0.754Ge0.246 alloy. Using these results, we compare our results for the thermoelectric figure-of-merit with previously reported results based on an empirical approach for phonon conductivity.

Keywords

thermal conductivitythermoelectricsemiconducting
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1404: Symposium W – Phonons in Nanomaterials–Theory, Experiments and Applications , 2012 , mrsf11-1404-w04-03
Copyright
Copyright © Materials Research Society 2012

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References

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