Percolation with excluded small clusters and Coulomb blockade in a granular system
- 73 Downloads
We consider dc-conductivity σ of a mixture of small conducting and insulating grains slightly below the percolation threshold, where finite clusters of conducting grains are characterized by a wide spectrum of sizes. The charge transport is controlled by tunneling of carriers between neighboring conducting clusters via short “links“ consisting of one insulating grain. Upon lowering temperature small clusters (up to some T-dependent size) become Coulomb blockaded, and are avoided, if possible, by relevant hopping paths. We introduce a relevant percolational problem of next-nearest-neighbors (NNN) conductivity with excluded small clusters and demonstrate (both numerically and analytically) that σ decreases as power law of the size of excluded clusters. As a physical consequence, the conductivity is a power-law function of temperature in a wide intermediate temperature range. We express the corresponding index through known critical indices of the perco lation theory and confirm this relation numerically.
KeywordsJETP Letter Percolation Threshold Near Neighbor Critical Cluster Coulomb Blockade
Unable to display preview. Download preview PDF.
- 1.Disorder and Granular Media, Ed. by D. Bideau and A. Hansen (North-Holland, Amsterdam, 1993).Google Scholar
- 3.D. Stauffer and A. Aharony, Introduction to Percolation Theory (Taylor and Fransis, London, 1994).Google Scholar
- 4.A. Bunde and S. Havlin, “Percolation I,” in Fractals and Disordered Systems, Ed. by A. Bunde and S. Havlin (Springer, Berlin, 1996).Google Scholar
- 5.Nanocomposite Science and Technology, Ed. by P. M. Ajayan, L. S. Schadler, and P. V. Braun (Wiley-VCH, Weinheim, 2003).Google Scholar
- 6.Single Electron Tunnelling, Ed. by H. Grabert and M. H. Devoret (Plenum, New York, London, 1992).Google Scholar
- 11.M. V. Feigelman and A. S. Ioselevich, to be published.Google Scholar
- 12.B. I. Shklovskii and A. L. Efros, Electronic Properties of Doped Semiconductors (Springer, Berlin, 1984).Google Scholar
- 16.A. S. Skal and B. I. Shklovskii, Sov. Phys. Semicond. 8, 1586 (1974); P. G. de Gennes, J. de Phys. 37, L1 (1976).Google Scholar