Electron localization in granular materials

被引:1
作者
Dumpich, G
Carl, A
Mikitisin, P
机构
[1] Experimentelle Tieftemperaturphysik, Gerhard-Mercator-Univ. Duisburg, D-47048 Duisburg
来源
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 1996年 / 217卷
关键词
granular materials; transmission electron microscopy; percolation threshold;
D O I
10.1016/S0921-5093(96)10280-X
中图分类号
TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
We have investigated the structural and electrical properties of granular Pd/C as well as granular Au/C thin films. As revealed by transmission electron microscopy the films consist of small metallic clusters of either Pd or Au embedded within amorphous carbon. Films with low metal volume fraction, x consist of structurally isolated clusters and show exponential resistance behavior. Above the so-called percolation threshold x(p), metallic clusters form a percolating network rendering metallic conductivity. For metallic films with x much greater than x(p) we observe two dimensional (2d) electronic transport behavior at low temperatures via small additional contributions to the Boltzmann-resistance as arising from weak electron localization (WEL) and enhanced electron-electron interaction (EEI). When approaching the percolation threshold these additional resistance contributions grow in absolute magnitude and the 2d transport behavior changes to 3d-behavior close to x(p). For both cases resistance as well as magnetoresistance data can be well explained using theories for WEL and EEI in 2d and 3d respectively.
引用
收藏
页码:353 / 357
页数:5
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