Charge transport through a SET with a mechanically oscillating island

TL;DR

This paper investigates how mechanical oscillations of a nanomechanical island in a single-electron transistor affect its electrical transport properties, revealing how oscillation characteristics can be inferred from current noise spectra.

Contribution

It introduces a model linking mechanical vibrations of the SET island to measurable electrical transport features, enabling characterization of oscillation amplitude and frequency.

Findings

Oscillations cause distinct features in the noise spectrum.

Harmonic oscillations produce a delta peak in the noise spectrum.

Transport properties can be used to infer island oscillation parameters.

Abstract

We consider a single-electron transistor (SET) whose central island is a nanomechanical oscillator. The gate capacitance of the SET depends on the mechanical displacement, thus, the vibrations of the island vibrations may strongly influence the current-voltage characteristics, current noise, and higher cumulants of the current. Harmonic oscillations of the island and oscillations with random amplitude (e.g., due to the thermal activation) change the transport characteristics in a different way. The noise spectrum has a peak at the frequency of the island oscillations; when the island oscillates harmonically, the peak reduces to a $\delta$-peak. We show that knowledge of the SET transport properties helps to determine in what way the island oscillates, to estimate the amplitude, and the frequency of the oscillations.