Suppression and enhancement of shot noise in transport through localised states

摘要

By studying shot noise we are able to reveal important details of 1D and 2Dtransport in the insulating regime of conduction at T = 4:2 K. We have found that 1D and2D geometries of hopping paths manifest themselves in shot noise in a very different way. Itis shown that the suppression of shot noise in hopping conduction depends on the distributionfunction of hopping distances in the conducting paths. We also study the effect of the Coulombinteraction between localised states on shot noise in resonant tunnelling across a short 2Dbarrier. When the current is carried by two interacting impurities, shot noise turns out to beconsiderably enhanced with respect to its Poisson value. With decreasing temperature downto T = 70 Mk the enhancement of shot noise becomes even stronger.