Ultrasensitive Displacement Noise Measurement of Carbon Nanotube Mechanical Resonators

Abstract

Mechanical resonators based on a single carbon nanotube are exceptional sensors of mass and force. The force sensitivity in these ultralight resonators is often limited by the noise in the detection of the vibrations. Here, we report on an ultrasensitive scheme based on a RLC resonator and a low-temperature amplifier to detect nanotube vibrations. We also show a new fabrication process of electromechanical nanotube resonators to reduce the separation between the suspended nanotube and the gate electrode down to ∼150 nm. These advances in detection and fabrication allow us to reach displacement sensitivity. Thermal vibrations cooled cryogenically at 300 mK are detected with a signal-to-noise ratio as high as 17 dB. We demonstrate force sensitivity, which is the best force sensitivity achieved thus far with a mechanical resonator. Our work is an important step toward imaging individual nuclear spins and studying the coupling between mechanical vibrations and electrons in different quantum electron transport regimes.

Cooling and self-oscillation in a nanotube electromechanical resonator

“…Electron transport measurements indicate that electrons are in the Kondo regime [21]. A regular shell filling with Kondo ridges at zero source-drain bias is observed upon sweeping V g Energy decay measurements of thermal vibrations reveal that the quality factor Q = 6.8 · 10 6 is remarkably high when compared to previous works [24][25][26]. This is also higher than the quality factor inferred from the spectral resonance linewidth, since the energy decay rate is smaller than the spectral resonance linewidth (Figs.…”

“…As a result, the force sensitivity of the resonator is record high [26], and the effect of the electron-vibration coupling is expected to be especially large.…”

“…1a). We detect the electrical current from the drain electrode using a RLC resonator with frequency ω RLC = 2π · 1.27 MHz and a high-electron-mobility-transistor amplifier [26]. We record the differential conductance G diff of the device by applying an oscillating voltage V ac sd to the source electrode with the frequency set at ω RLC .…”

Layering Transition in Superfluid Helium Adsorbed on a Carbon Nanotube Mechanical Resonator

“…The mechanical vibrations of the fundamental mode of the nanotube are driven capacitively and measured electrically ( Fig. 1c) [17][18][19]. The resonance frequency can be tuned by a large amount around 30 MHz when tuning the gate voltage ( Figs.…”

Properties of the Geometric Phase in Electromechanical Oscillations of Carbon-Nanotube-Based Nanowire Resonators

“…In particular, CNT-based nanowire resonators have attracted considerable interest as nanoscale mechanical devices due to their extraordinary sensitivities with high-quality factors to a small perturbation from surroundings. Suspended CNT-based nanowire resonators are promising candidates for apparatuses measuring a wide range of physical quantities, such as EM waves [2], small forces [7], masses [8], temperatures [9], and noises [10].…”