Hostname: page-component-7bb8b95d7b-s9k8s Total loading time: 0 Render date: 2024-09-11T07:11:25.722Z Has data issue: false hasContentIssue false

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
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
Get access

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.

Type
Research Article
Copyright
Copyright © Materials Research Society 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Minnich, A. J. et al. ., J. Energy Environ. Sci. 2, 466 (2009).Google Scholar
[2] Meddins, H. R. and Parrott, J. E., J. Phys. C: Solid State Phys. 9, 1263 (1976).Google Scholar
[3] McKelvey, J. P., Solid State and Semiconductor Physics (International Edition) (Harper & Row, New York, 1966).Google Scholar
[4] Blakemore, J. S., Solid State Physics (W. B. Saunders Company, Philadelphia, 1970), p. 262.Google Scholar
[5] Goldsmid, H. J., Introduction to Thermoelectricity (Springer-Verlag, Berlin, 2010).Google Scholar
[6] Drabble, J. R. and Goldsmid, H. J., Thermal Conduction in Semiconductors (Pergamon Press, Oxford, 1961).Google Scholar
[7] Srivastava, G. P., The Physics of Phonons (Adam Hilger, Bristol, 1990).Google Scholar
[8] Slack, G. A., Phys. Rev. B 126, 427 (1962).Google Scholar
[9] Madelung, O., Schulz, M. and Weiss, H. (eds.), Landolt-B¨ornstein Numerical Data and Functional Relationships in Science and Technology: Group III, Volume 17a (Springer-Verlag, Berlin, 1982).Google Scholar
[10] Monkhorst, H. J. and Pack, J.D., Phys. Rev. B 13, 5188 (1976).Google Scholar
[11] Baroni, S. et al. ., Rev. Mod. Phys. 73, 515 (2001).Google Scholar
[12] Gianozzi, P. et al. ., J. Phys. Cond. Mat. 21, 395502 (2009); the code and the pseudo-potentials Si.pz-vbc.UPF and Ge.pz-bhs.UPF used are available from http://www.quantum-espresso.org.Google Scholar
[13] AlShaikhi, A. and Srivastava, G. P., Phys. Rev. B 76, 195205 (2007).Google Scholar