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We measure the energy relaxation rate of single- and few-layer molybdenum disulphide (MoS2) nanomechanical resonators by detecting the resonator ring-down. Recent experiments on these devices show a remarkably low quality (Q)-factor when taking spectrum measurements at room temperature. The origin of the low spectral Q-factor is an open question, and it has been proposed that besides dissipative processes, frequency fluctuations contribute significantly to the resonance line-width. The spectral measurements performed thus far however, do not allow one to distinguish these two processes. Here, we use time-domain measurements to quantify the dissipation. We compare the Q-factor obtained from the ring-down measurements to those obtained from the thermal noise spectrum and from the frequency response of the driven device. In few-layer and single-layer MoS2 resonators, the two are in close agreement, which demonstrates that the spectral line-width in MoS2 membranes at room temperature is limited by dissipation, and that excess spectral broadening plays a negligible role. [ABSTRACT FROM AUTHOR]

We have employed a feedback cooling scheme, which combines high-frequency mixing with digital signal processing. The frequency and damping rate of a 2 MHz micromechanical resonator embedded in a dc SQUID are adjusted with the feedback, and active cooling to a temperature of 14.3 mK is demonstrated. This technique can be applied to GHz resonators and allows for flexible control strategies. [ABSTRACT FROM AUTHOR]

We demonstrate magnetomotive drive and detection of doubly clamped string resonators in water. A compact 1.9 T permanent magnet is used to detect the fundamental and higher flexural modes of 200 μm long resonators. Good agreement is found between the magnetomotive measurements and optical measurements performed on the same resonator. The magnetomotive detection scheme can be used to simultaneously drive and detect multiple sensors or scanning probes in viscous fluids without alignment of detector beams. [ABSTRACT FROM AUTHOR]

We present a method for efficient spectral readout of mechanical resonator arrays in dissipative environments. Magnetomotive drive and detection are used to drive double clamped resonators in the nonlinear regime. Resonators with almost identical resonance frequencies can be tracked individually by sweeping the drive power. Measurements are performed at room temperature and atmospheric pressure. These conditions enable application in high throughput resonant sensor arrays. [ABSTRACT FROM AUTHOR]

We have fabricated suspended metal paddle resonators with carbon nanotubes functioning as self-detecting torsional springs. We observe gate-tunable resonances that either tune to higher or to lower frequencies when increasing the dc voltage on the back gate. We attribute the former modes to flexural vibrations of the paddle resonator, while the latter ones are identified as torsional vibrations. Compared to top-down silicon fabricated paddle resonators, nanotube springs have smaller torsional spring constants and provide a larger frequency tunability. [ABSTRACT FROM AUTHOR]

Complex oxide thin films and heterostructures exhibit a variety of electronic phases, often controlled by the mechanical coupling between film and substrate. Recently it has become possible to isolate epitaxially grown single-crystalline layers of these materials, enabling the study of their properties in the absence of interface effects. In this work, we use this technique to create nanomechanical resonators made out of SrTiO3 and SrRuO3. Using laser interferometry, we successfully actuate and measure the motion of the nanodrum resonators. By measuring the temperature-dependent mechanical response of the SrTiO3 resonators, we observe signatures of a structural phase transition, which affects both the strain and mechanical dissipation in the resonators. Here, we demonstrate the feasibility of integrating ultrathin complex oxide membranes for realizing nanoelectromechanical systems on arbitrary substrates and present a novel method of detecting structural phase transitions in these exotic materials. Thin films of complex oxides can be grown and transferred on substrates, which provides opportunities for their manipulation, characterization and potential applications. Here, the authors fabricate and characterize nanodrum resonators of suspended thin single-crystal complex oxides and investigate the temperature dependent properties and associated phase transitions of the isolated ultrathin form. [ABSTRACT FROM AUTHOR]