Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-27T02:11:18.893Z Has data issue: false hasContentIssue false
  • English
  • Français

Atomic Ordering, Electronic Structure, and Transport Properties of LAST-m Systems

Published online by Cambridge University Press:  01 February 2011

S. D. Mahanti ,
Khang Hoang  and
Salameh Ahmad
S. D. Mahanti
Affiliation:
[email protected], Michigan State University, Department of Physics and Astronomy, 4269, BPS Building, East Lansing, MI, 48824-2320, United States, 517-355-9200-2303, 517-353-4500
Khang Hoang
Affiliation:
[email protected], Michigan State University, Department of Physics and Astronomy, East Lansing, MI, 48824-2320, United States
Salameh Ahmad
Affiliation:
[email protected], Michigan State University, Department of Physics and Astronomy, East Lansing, MI, 48824-2320, United States
Get access

Abstract

In recent years, LAST-m (AgPbmSbTem+2) and related materials have emerged as potential high performance high temperature thermoelectrics. These compounds are obtained by starting from PbTe, and replacing pairs of Pb2+ ions by (Ag1+, Sb3+) pairs. One example is LAST-18. When optimally doped, this compound has thermoelectric figure of merit ZT=1.7 at 700K. This large ZT is most likely due to very low lattice thermal conductivity, caused by phonon scattering from nanostructures. These nanostructures involve clustering and ordering of Ag, Sb, and Pb ions. Possible origins of this atomic ordering and how the presence of nanostructures affects the electronic structure near the band gap region are discussed. The temperature (T) dependence of electrical conductivity σ (∼T2.2 in the range 300K <T< 900K) in n-type PbTe is analyzed in terms of the T-dependence of different physical quantities contributing to transport. We find that the dominant contribution comes from the explicit T-dependence of relaxation time rather than its energy dependence. The T-dependence of chemical potential is also significant in the concentration range of interest. Electronic thermal conductivity for constant field (κel,E) and for constant current (κel,J) are found to differ considerably at high temperatures and the Weidemann-Franz (WF) law κel,J = LoσT, where Lo =2x10−8WΩ/K is the Lorentz number, overstimates κel,J by nearly 60% at 800K for carrier concentration n=5x1019/cm3. As a result, one tends to underestimate the lattice contribution κlatt = κexp - κel,J. We give theoretical values of effective Lorentz number L = κel.J/σT for different n and T.

Keywords

electronic structurethermoelectricitynanostructure
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1044: Symposium U – Thermoelectric Power Generation , 2007 , 1044-U04-06
Copyright
Copyright © Materials Research Society 2008

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

1. Uher, C., Chemistry, Physics, and Materials Science of Thermoelectric Materials: Beyond Bismuth Telluride“, Edited by Kanatzidis, M. G., Mahanti, S. D., and Hogan, T. P., Kluwer Academic/Plenum Publishers, New York (2003), p. 121.Google Scholar
2. Harman, T. C. et al. , Science 297, 2229 (2002).Google Scholar
3. Hsu, K. F. et al. , Science 303, 818 (2004).Google Scholar
4. Takahata, K. and Terasaki, I., Jpn. J. Appl. Phys. 41, 763 (2002).Google Scholar
5. Ziman, J. M., Principles of The Theory of Solids (Camb. Univer Press, NY 1964), p 179.Google Scholar
6. Hoang, K., Desai, K., and Mahanti, S. D., Phys. Rev. B 72, 064102 (2005).Google Scholar
7. Quarez, E. et al. , J. Am. Chem. Soc. 127, 9177 (2005); P. F. P. Poudeu et al., Angew. Chem. Int. Ed. 45, 3835 (2006).Google Scholar
8. Hoang, K., Atomic and Electronic Structures of Novel Ternary and Quaternary Narrow Band-Gap Semiconductors, Ph. D. Thesis, Michigan State University (2007).Google Scholar
9. Hoang, K. et al. , Phys. Rev. Letters 99, 156403 (2007).Google Scholar
10. Bilc, D. et al. , Phys. Rev. Letters 93, 146403 (2004).Google Scholar
11. Hazama, H., Mizutani, U., and Asahi, R., Phys. Rev. B 73, 115108 (2006).Google Scholar
12. Volkov, B. A., Ryabova, L. I., and Khokhlov, D. R., Phys.-Usp. 45, 819 (2002).Google Scholar
13. Ahmad, S., Hoang, K., and Mahanti, S. D., Phys. Rev. Lett. 96, 056403 (2006); 96, 169907(E)(2006).Google Scholar
14. Ahmad, S. et al. , Phys. Rev. B 74, 155205 (2006).Google Scholar
15. Mahan, G. D. and Sofo, J. O., Proc. Natl. Acad. Sci. U. S. A. 93, 7436 (1996).Google Scholar
16. Han, M.-K. et al. , (to be submitted to Chemistry of Materials).Google Scholar
17. Sootman, J. et al. (unpublished).Google Scholar
18. Effimova, B. A. et al. , Soviet Physics – Semiconductors 4, 1653 (1971).Google Scholar
19. Bilc, D., Mahanti, S. D., and Kanatzidis, M. G., Phys. Rev. B 74, 125202 (2006).Google Scholar
20. Ahmad, S., Defect Structure and Transport Properties of Narrow Gap Semiconductor PbTe and Related Ststems, Ph. D. Thesis, Michigan State University (2007); Also see C.M.Bhandari and D. D. M. Rowe, J. Phys. D; Appl. Phys. 18, 873 (1985).Google Scholar
21. Drabble, J. R. and Goldsmid, H. J., International Series of Monographs on Semiconductors: Thermal Conduction in Semiconductors, Vol. 4 (Pergammon Press, 1961).Google Scholar
22. Hohenberg, P. and Kohn, W., Phys. Rev. 136, B864 (1964); W. Kohn and L. J. Sham, Phys. Rev. 140, A1133 (1965).Google Scholar
23. Perdew, J. P. and Wang, Y., Phys. Rev. B 45, 13244 (1992).Google Scholar
24. Aulber, W. G., Jonsson, L., and Wilkins, J. W., Solid State Physics 54, 1 (2000).Google Scholar