Semimetal


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semimetal

[¦sem·ē′med·əl]
(chemistry)

Semimetal

 

a substance occupying an intermediate position between metals and semiconductors with regard to electrical properties. A characteristic feature of semimetals is a weak overlapping of the valence band and conduction band. This indicates that semimetals remain conductors of electric current down to a temperature of absolute zero and yet have a low (compared to metals) concentration of current carriers—approximately 1018-1020 cm-3. Semimetals include Bi, Sb, As, and graphite.

Current carriers in semimetals exhibit high mobility and low effective mass. These properties make semimetals the most suitable substances for use in observing size effects, semimetal-dielec-tric phase transitions in strong magnetic fields, and many other phenomena.

REFERENCES

Fizika metallov. Vol. 1: Elektrony. Edited by J. Ziman. Moscow, 1972. (Translated from English.)
Lifshits, I. M., M. Ia. Azbel’, and M. I. Kaganov. Elektronnaia teoriia metallov. Moscow, 1971.
Fal’kovskii, L. A. “Fizicheskie svoistva vismuta.” Uspekhi fizicheskikh nauk, 1968, vol. 94, issue 1, p. 3.
Larson, D. C. “Razmernye effekty v elektroprovodnosti tonkikh metal-licheskikh plenok i provolok”. In Fizika tonkikh plenok, vol. 6. Moscow, 1973. (Translated from English.)

E. M. EPSHTEIN

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