Observation of Strong Coulomb Blockade in Resistively Isolated Tunnel Junctions

TL;DR

This study demonstrates strong Coulomb blockade effects in resistively isolated tunnel junctions at millikelvin temperatures, showing scaling behavior and agreement with environmental tunneling models.

Contribution

It provides experimental evidence of Coulomb blockade in resistively isolated junctions and confirms theoretical predictions including environmental effects.

Findings

Coulomb blockade observed at temperatures 60mK to 230mK

Zero-bias resistance up to 10^4 times the tunnel resistance

I-V curves scale with V/T and follow a power law

Abstract

We report measurements of the Coulomb-blockade current in resistively isolated (R_{Isol} >> h/e^{2}) tunnel junctions for the temperature range 60mK $We report measurements of the Coulomb-blockade current in resistively isolated ($R_{Isol}\gg h/e^{2})$ tunnel junctions for the temperature range 60mK < T < 230mK where the charging energy E_{c} is much greater than the thermal energy. A zero-bias resistance R_{0} of up to 10^{4}R_{T} (the tunnel resistance of the bare junction) is obtained. For eV << E_{c}, the I-V curves for a given R_{Isol} scale as a function of V/T, with I \propto V^{\alpha (R_{Isol})} over a range of V. The data agree well with numerical calculations of the tunneling rate that include environmental effects.