Abstract
We obtain simple, but rigorous bounds for impurity quantum states, for a tight-z binding model on random fractal structures. From these we conclude that a “typical„ state on a percolation cluster decays with Euclidean distance r as exp [- cra], with 1Š≤ŠaŠ≤Šςc, where rςcis the average chemical distance. Averaging over all random configurations yields regular exponential decay, aŠ=Š1. Our bounds indicate that the probability of a classical random walker to reach distance r at time t decays as exp [- (rd/w/t)α], tŠ< Šrdw, with 1/(dw - 1)Š≤ŠαŠ≤Šςc/(dw - ςc). For the fully averaged probability we expect αŠ=Š1/(dw - 1). The thermally activated hopping conductivity between impurities on a random structure with fractal dimensionality D is found to behave as exp [- (T0/T)β], with βŠ=Šςc/(D + ςc).
Original language | English |
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Pages (from-to) | 1355-1360 |
Number of pages | 6 |
Journal | EPL |
Volume | 4 |
Issue number | 12 |
DOIs | |
State | Published - 15 Dec 1987 |
Externally published | Yes |
ASJC Scopus subject areas
- General Physics and Astronomy