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Icosahedral Boron-Rich Solids as Refractory Semiconductors

Published online by Cambridge University Press:  25 February 2011

David Emin*
Affiliation:
Sandia National Laboratories, Albuquerque, New Mexico, 87185, USA.
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Abstract

Icosahedral boron-rich solids are refractory materials composed of twelve-atom boron-rich icosahedral units with strong intericosahedral linkages. These distinctive structures admit unusual electronic and thermal transport properties. Here the distinctive (three-center) bonding which underlies these materials is first described. Then it is shown how insulators, semiconductors and highly degenerate (metal-like) materials emerge from the same basic structure with appropriate substitutions.

The electronic transport of the boron carbides is then addressed. The boron carbides are degenerate p-type semiconductors in which the charge carriers are diamagnetically aligned pairs of electrons which hop between icosahedra. Uniquely, this thermally activated hopping conductivity increases with increasing hydrostatic pressure. However, the Seebeck coefficient (thermoelectric power) is uncharacteristic of a degenerate semiconductor. Namely, the Seebeck coefficient is typically both large and an increasing function of temperature. In addition, despite the hardness and refractory character of these materials, their thermal conductivities can be surprisingly low with a glass-like temperature dependence. These features are manifestations of the distinctive structure and bonding of these solids. In fact, this novel mix of properties makes the boron carbides exceptionally good very-high-temperature p-type thermoelectric materials.

Icosahedral boron-rich solids have additional potential as high temperature semiconductors. In particular, the wide-gap icosahedral boronrich pnictides, B12P2 and B12As2, may be doped to form wide-gap refractory semiconductors. For example, replacement of the group V element with either a group VI or a group IV element is expected to yield n-type and ptype material, respectively.

Type
Research Article
Copyright
Copyright © Materials Research Society 1987

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References

REFERENCES

1. Lipscomb, W. N., Boron Hydrides (Benjamin, New York, 1963).Google Scholar
2. Morosin, B., Mullendore, A. W., Emin, D. and Slack, G. A., in Boron-Rich Solids (AlP Conf. Proc. 140) Emin, D., Aselage, T. L. Beckel, C. L., Howard, I. A. and Wood, C., eds. (ALP, New York, 1986) p. 70.Google Scholar
3. Longuet-Higgens, H. C., Roberts, M. de V., Proc. R. Soc. London, Ser. A 230, 110 (1955).Google Scholar
4. Emin, David, in Physics Today (AlP, Jan. 1987) p. 55.Google Scholar
5. Golikova, O. A., Phys. Status Solidi A 86, K51 (1984).Google Scholar
6. Slack, G. A., McNelly, T. F., Taft, E. A., J. Chem. Phys. Solids 44, 1009 (1983).Google Scholar
7. Golikova, O. A., this volume.Google Scholar
8. Wood, C. and Emin, D., Phys. Rev. B 29, 4582 (1985).Google Scholar
9. Bouchacourt, K. and Thevenot, F., J. Less-Common Metals 82, 219 (1981).Google Scholar
10. Glaser, F. W., Moskowitz, D. and Post, B., J. Appl. Phys. 24, 731 (1953).Google Scholar
11. Venturini, E. L., Emin, D. and Aselage, T. L., the volume.Google Scholar
12. Emin, David and Holstein, T., Ann. Phys. (N.Y.) 53, 439 (1969).Google Scholar
13. Emin, David, Comm. in Solid State Phys. II, 59 (1983).Google Scholar
14. Emin, David, Phys. Rev. Lett. 32, 3030 (1974).Google Scholar
15. Azevedo, L. J., Venturini, E. L., Emin, D. and Wood, C., Phys. Rev. B 32, 7970 (1985).Google Scholar
16. Venturini, E. L., Azevedo, L. J., Emin, D. and Wood, C., in Boron-Rich Solids (AIP Conf. Proc. 140) Emin, D., Aselage, T. L. Beckel, C. L., Howard, I. A. and Wood, C., eds. (ALP, New York, 1986) p. 292.Google Scholar
17. Howard, I. A., Beckel, C. L. and Emin, D., Phys. Rev. B 35, 2929 (1987).Google Scholar
18. Howard, I. A., Beckel, C. L. and Emin, D., Phys. Rev. B 35, xxxx (1987).Google Scholar
19. Howard, I. A., Beckel, C. L. and Emin, D., this volume.Google Scholar
20. Green, T. A. and Emin, D., to be published.Google Scholar
21. Pitochellli, A. R. and Hawthorne, M. F., Amer. J. Chem. Soc. 82, 3228 (1960).Google Scholar
22. Emin, D., Samara, G. A. and Wood, C., Proc. 17-th Int. Conf. Phys. of Semiconductors, J. D.Chadi and W. A. Harrison, eds. (Springer-Verlag, New York, 1985) p. 1349.Google Scholar
23. Emin, D., Samara, G. A., Azevedo, L. J., Venturini, E. L., Madden, H. H., Nelson, G. C., Shelnutt, J. A., Morosin, B. and Moss, M., J. Less-Common Metals 117, 415 (1986).Google Scholar
24. Emin, D., Samara, G. A. and Wood, C., Phys. Rev. B32, 2315 (1985).Google Scholar
25. Schafroth, M. R., Blatt, J. M. and Butler, S. T., Helv. Phys. acta 30, 93 (1957).Google Scholar
26. Alexandrov, A. and Ranninger, J, Phys. Rev. B 24, 1164 (1981).Google Scholar
27. Landau, L. D., Zh. Eksp, Teor. Fiz., 11, 592 (1941).Google Scholar
28. Emin, D., to be published.Google Scholar
29. Callen, H. B., Thermodynamics, (Wiley, New York, 1960) p. 299.Google Scholar
30. Emin, D., Phys. Rev. Lett. 35, 882 (1975).Google Scholar
31. Aselage, T. L., Emin, D. and Wood, C., this volume.Google Scholar
32. Wood, C., in Boron-Rich Solids (AIP Conf. Proc. 140) Emin, D., Aselage, T. L. Beckel, C. L., Howard, I. A. and Wood, C., eds. (AIP, New York, 1986) p. 206.Google Scholar
33. Mackinnon, I. D. R., Aselage, T. and Deusen, S. B. Van, in Boron-Rich Solids (AIP Conf. Proc. 140) Emin, D., Aselage, T. L. Beckel, C. L., Howard, I. A. and Wood, C., eds. (AIP, New York, 1986) p. 114.Google Scholar
34. Mackinnon, I. D. R. and Smith, Katherine L., this volume.Google Scholar
35. Slack, G. A., Oliver, D. W. and Horn, F. H., Phys. Rev. B 4, 1714 (1971).Google Scholar
36. Wood, C., Emin, D. and Gray, P. E., Phys. Rev. B 31, 6811 (1985).Google Scholar
37. Turkes, P. R. H., Swartz, E. T. and Pohl, R. O., in Boron-Rich Solids (AIP Conf. Proc. 140) Emin, D., Aselage, T. L. Beckel, C. L., Howard, I. A. and Wood, C., eds. (AIP, New York, 1986) p. 346.Google Scholar
38. Fischer, H. E., Swartz, E. T., Turkes, P. R. H. and Pohl, R. O., this volume.Google Scholar
39. Ioffe, A. F., Soy. Phys. Solid 1, 141 (1959).Google Scholar
40. Emin, D., Howard, I. A., Green, T. A. and Beckel, C. L., this volume.Google Scholar
41. Moss, M., this volume.Google Scholar