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Metal—Insulator Transition in Boron Carbide
Author(s) -
Werheit H.,
de Groot K.
Publication year - 1980
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220970126
Subject(s) - boron carbide , impurity , materials science , seebeck coefficient , electrical resistivity and conductivity , boron , variable range hopping , carbide , thermal conduction , metal , atmospheric temperature range , metal–insulator transition , analytical chemistry (journal) , condensed matter physics , thermal conductivity , chemistry , metallurgy , thermodynamics , composite material , electrical engineering , physics , organic chemistry , chromatography , engineering
The electrical conductivity and the thermoelectric power of boron carbide are investigated in the temperature range from 80 to 700 K on samples of compositions between B 12.94 C 2.06 and B 10.59 C 4.41 . While the extrinsic thermal activation of free carriers dominates the electronic transport at high temperatures, at low temperatures a metal—insulator transition occurs depending on the C content. Lower C contents than B 12 C 3 cause variable‐range hopping (In σ ∼ T −1/4 ) whereas higher contents lead to impurity‐band conduction. The overlap of two impurity bands (possibly Hubbard bands) attributed to the carbon in boron carbide is assumed.