Crossover from global to local rule for the Coulomb blockade in small tunnel junctions.

摘要: We have investigated several single and double aluminum tunnel junctions in the nonsuperconducting state. Current-voltage (I-V) characteristics were measured up to voltages corresponding hundred times e/C, where C is capacitance of each junction. The individual had capacitances order 0.5 fF resistances 50--150 k\ensuremath{\Omega}. offset voltage, defined as ${\mathit{V}}_{\mathrm{off}}$=V-I/(dI/dV), resistance independent for given junction capacitances, but depends on bias voltage. For a voltage very small low voltages, it approaches local-rule value e/2C at high voltages. global rule applies equals ${\mathit{V}}_{\mathrm{off}}$=e/${\mathit{C}}_{\mathrm{\ensuremath{\Sigma}}}$, ${\mathit{C}}_{\mathrm{\ensuremath{\Sigma}}}$=2C+${\mathit{C}}_{0}$. At large local contributes with so that ${\mathit{V}}_{\mathrm{off}}$=e/C. This paper shows careful analysis has be made determine values involved.