Determination of Coulomb-blockade resistances and observation of the tunneling of single electrons in small-tunnel-junction circuits

Abstract

Coulomb-blockade effects greatly enhance the resistance of low-capacitance tunnel-junction circuits at low bias and temperature. Experiments which involve the charging of small capacitances through such circuits are used to determine semiquantitatively the degree of this enhancement. Resistances of ≳${10}^{17}$ Ω have been observed for four-series-junction circuits whose individual junctions have resistances ∼${10}^6$ Ω. Two-series-junction circuits show lesser enhancements. For the higher resistances, one can observe directly the charging proceeding in discrete steps as individual electrons tunnel through the circuits.