Improving the read-out of the resonance frequency of nanotube mechanical resonators

TL;DR

This paper presents an improved electrical detection method for nanotube resonators, achieving unprecedented sensitivity and stability, with potential applications in mass spectrometry and surface science.

Contribution

The authors develop a low-noise detection technique using an RLC resonator and cooled HEMT amplifier, significantly enhancing the measurement of nanotube resonance frequencies.

Findings

Resonance frequency resolution surpasses previous methods.

Noise limited by the resonator itself, not measurement imprecision.

Allan deviation reaches ~10^-5 at 125 ms, indicating high stability.

Abstract

We report on an electrical detection method of ultrasensitive carbon nanotube mechanical resonators. The noise floor of the detection method is reduced using a RLC resonator and an amplifier based on a high electron mobility transistor cooled at 4.2 K. This allows us to resolve the resonance frequency of nanotube resonators with an unprecedented quality. We show that the noise of the resonance frequency measured at 4.2 K is limited by the resonator itself, and not by the imprecision of the measurement. The Allan deviation reaches ~10^-5 at 125 ms integration time. When comparing the integration time dependence of the Allan deviation to a power law, the exponent approaches ~1/4. The Allan deviation might be limited by the diffusion of particles over the surface of the nanotube. Our work holds promise for mass spectrometry and surface science experiments based on mechanical nano-resonators.