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 \ensuremath{\gtrsim}${10}^{17}$ \ensuremath{\Omega} have been observed for four-series-junction circuits whose individual junctions have resistances \ensuremath{\sim}${10}^{6}$ \ensuremath{\Omega}. 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.