Observation of Partially Suppressed Shot Noise in Hopping Conduction
  We have observed shot noise in the hopping conduction of two dimensional carriers confined in a p-type SiGe quantum well at a temperature of 4K. Moreover, shot noise is suppressed relative to its ``classical'' value 2eI by an amount that depends on the length of the sample and carrier density, which was controlled by a gate voltage. We have found a suppression factor to the classical value of about one half for a 2 $\mu$m long sample, and of one fifth for a 5 $\mu$m sample. In each case, the factor decreased slightly as the density increased toward the insulator-metal transition. We explain these results in terms of the characteristic length ($\simeq 1\mu$m in our case) of the inherent inhomogeneity of hopping transport. 
V. V. Kuznetsov, E. E. Mendez (1), E. T. Croke, X. Zuo, G. L. Snider   (2) ((1) SUNY at Stony Brook, (2) University of Notre...