Semimetal

(redirected from Semimetallic)
Also found in: Dictionary.

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

References in periodicals archive ?
Physical, chemical and crystallographic properties: Luster: semimetallic to metallic.
Gallium is a semimetallic element that inhibits ribonucleotide reductase, an enzyme that promotes tumor growth, according to Titan.
Only the semimetallic and NAO materials have shown promise for common automotive brake lining applications.
Now some European manufacturers use four-wheel disk brakes and semimetallic brake pads as a means of eliminating asbestos from passenger cars.
A small percentage of medium trucks are now being produced with disk brakes and semimetallic pads.
Recent evidence from a project in India by the same research group showed decreased lung function similar to that of smokers in adults exposed to the semimetallic carcinogen.
Though semimetallic materials have been substituted for asbestos in front disk brakes, they provide less traction when new.
High Temperature Wear of Semimetallic Disc Brake Pads", Wear 36, 1978 pp 213-218.