EVIDENCE FOR SUPERLOCALIZATION ON A FRACTAL NETWORK IN CONDUCTIVE CARBON-BLACK POLYMER COMPOSITES

被引:125
作者
VANDERPUTTEN, D [1 ]
MOONEN, JT [1 ]
BROM, HB [1 ]
BROKKENZIJP, JCM [1 ]
MICHELS, MAJ [1 ]
机构
[1] KONINKLIJKE SHELL EXPTL PROD LAB, 1003 AA AMSTERDAM, NETHERLANDS
关键词
D O I
10.1103/PhysRevLett.69.494
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
The dc conductivity of carbon-black-polymer composites has been measured as a function of carbon-black concentration from just above the percolation threshold p(c) up to 33p(c), and in the temperature range from 4 to 300 K. To explain the temperature dependence we have modified the Mott-Deutscher model for variable-range hopping between superlocalized states on a fractal by assuming Coulomb-dominated hopping. Our data then yield the first experimental evidence of electron superlocalization, with a superlocalization exponent zeta = 1.94 +/- 0.06, close to theoretical estimates. The derived localization length is of the right order of magnitude.
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页码:494 / 497
页数:4
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