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Hopping Conductivity Beyond The Percolation Regime Probed By Shot-Noise Measurements

F. E. Camino·V. V. Kuznetsov·E. E. Mendez·M. E. Gershenson·D. Reuter·P. Schafmeister·A. D. Wieck
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Abstract

We have observed suppression of shot noise in the variable-range hopping regime for a two-dimensional electron gas whose localization length, xi, is controlled by a gate voltage. We have found that the suppression factor F (Fano factor) is approximately inversely proportional to the length of the system L (F=L0*/L) for a broad range of values of xi/L_0*, where L0* is the characteristic length. In the case xi/L0*<<1, we have identified L0* with the distance L0 between the hard hops along the sample length. On the other hand, when xi is of the order of L0*, we have observed that L0* does not agree with L0 calculated from the percolation model of hopping. We attribute this discrepancy to a breakdown of that model and to a reconstruction of the hopping paths.

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F. E. Camino, V. V. Kuznetsov, E. E. Mendez, M. E. Gershenson, D. Reuter, P. Schafmeister, A. D. Wieck. 2003-04-11. Hopping Conductivity Beyond The Percolation Regime Probed By Shot-Noise Measurements. https://doi.org/10.1103/physrevb.68.073313

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