標題: A critical path approach for elucidating the temperature dependence of granular hopping conduction
作者: Wu, Tsz Chun
Lin, Juhn-Jong
Sheng, Ping
電子物理學系
物理研究所
Department of Electrophysics
Institute of Physics
關鍵字: granular hopping conduction;insulator-conductor composites;critical path method;immediate-neighbor hopping
公開日期: 1-Oct-2018
摘要: We revisit the classical problem of granular hopping conduction's sigma ae exp[-(T (o) /T)(1/2)] temperature dependence, where sigma denotes conductivity, T is temperature, and T (o) is a sample-dependent constant. By using the hopping conduction formulation in conjunction with the incorporation of the random potential that has been shown to exist in insulator-conductor composites, it is demonstrated that the widely observed temperature dependence of granular hopping conduction emerges very naturally through the immediate-neighbor critical-path argument. Here, immediate-neighbor pairs are defined to be those where a line connecting two grains does not cross or by-pass other grains, and the critical-path argument denotes the derivation of sample conductance based on the geometric percolation condition that is marked by the critical conduction path in a random granular composite. Simulations based on the exact electrical network evaluation of finite-sample conductance show that the configurationaveraged results agree well with those obtained using the immediate-neighbor critical-path method. Furthermore, the results obtained using both these methods show good agreement with experimental data on hopping conduction in a sputtered metal-insulator composite Ag (x) (SnO2)(1-x) , where x denotes the metal volume fraction. The present approach offers a relatively straightforward and simple explanation for the temperature behavior that has been widely observed over diverse material systems, but which has remained a puzzle in spite of the various efforts made to explain this phenomenon.
URI: http://dx.doi.org/10.1007/s11467-018-0814-y
http://hdl.handle.net/11536/145263
ISSN: 2095-0462
DOI: 10.1007/s11467-018-0814-y
期刊: FRONTIERS OF PHYSICS
Volume: 13
Appears in Collections:Articles