Effect of Coulomb blockade on STM current through a granular film

TL;DR

This paper investigates how Coulomb blockade influences STM current in granular films, revealing a Coulomb staircase with potential applications in room-temperature single-electron devices through combined theoretical and experimental analysis.

Contribution

It demonstrates the impact of Coulomb blockade on STM current in granular films and shows room-temperature Coulomb staircase observation, suggesting new single-electron device possibilities.

Findings

Coulomb staircase observed at room temperature.

Period of CS determined by bottleneck capacitance.

Experimental and theoretical agreement on tunneling behavior.

Abstract

The electron transport through an array of tunnel junctions consisting of an STM tip and a granular film is studied both theoretically and experimentally. When the tunnel resistance between the tip and a granule on the surface is much larger than those between granules, a bottleneck of the tunneling current is created in the array. It is shown that the period of the Coulomb staircase(CS) is given by the capacitance at the bottleneck. Our STM experiments on Co-Al-O granular films show the CS with a single period at room temperature. This provides a new possibility for single-electron-spin-electronic devices at room temperature.