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Silicon carbide (SiC) has great potential for optomechanical applications due to its outstanding optical and mechanical properties. However, challenges associated with SiC nanofabrication have constrained its adoption in optomechanical devices, as embodied by the considerable optical loss or lack of integrated optical access in existing mechanical resonators. In this work, we overcome such challenges and demonstrate a low-loss, ultracompact optomechanical resonator in an integrated 4H-SiC-on-insulator (4H-SiCOI) photonic platform for the first time, to our knowledge. Based on a suspended 4.3-μm-radius microdisk, the SiC optomechanical resonator features low optical loss (<1  dB/cm), a high mechanical frequencyf_mof 0.95×10⁹  Hz, a mechanical quality factorQ_mof 1.92×10⁴, and a footprint of <1×10⁻⁵  mm². The correspondingf_m·Q_mproduct is estimated to be 1.82×10¹³  Hz, which is among the highest reported values of optomechanical cavities tested in ambient environment at room temperature. In addition, the strong optomechanical coupling in the SiC microdisk enables coherent regenerative optomechanical oscillations at a threshold optical dropped power of 14 μW, which also supports efficient harmonic generation at increased power levels. With such competitive performance, we envision a range of chip-scale optomechanical applications to be enabled by the low-loss 4H-SiCOI platform. 

We report the experimental demonstration of temperature compensated bilayer graphene two‐dimensional (2D) nanomechanical resonators operating in temperature range of 300 to 480 K. By using both microspectroscopy and scanning spectromicroscopy techniques, spatially visualized undriven thermomechanical motion is conveniently used to monitor both the resonance frequency and temperature of the device via noise thermometry while the device is photothermally agitated. Thanks to engineerable naturally integrated temperature compensation of the graphene and gold clamps that minimize variations of built‐in tension in a wide temperature range, very small linear TCfs of ≈−39 and −84 ppm K^−1 are achieved in the graphene nanomechanical resonators. The measured TCfs are orders of magnitude smaller than those in other 2D resonant nanoelectromechanical systems (NEMS). The intricately coupled thermal tuning and strain effects are further examined, elucidating that TCf can be further improved by optimizing device dimensions, which can be exploited for engineering highly stable NEMS resonators and oscillators for signal transduction and sensing applications. 

Microelectromechanical systems (MEMS) have emerged as highly attractive alternatives to conventional commercial off-the-shelf electronic sensors and systems due to their ability to offer miniature size, reduced weight, and low power consumption (i.e., SWaP advantages). These features make MEMS particularly appealing for a wide range of critical applications, including communication, biomedical, automotive, aerospace, and defense sectors. Resonant MEMS play crucial roles in these applications by providing precise timing references and channel selections for electronic devices, facilitating accurate filtering, mixing, synchronization, and tracking via their high stability and low phase noise. Additionally, they serve as key components in sensing applications, enabling detection and precise measurement of physical quantities for monitoring and control purposes across various fields. Temperature stability stands as a paramount performance specification for MEMS resonators and oscillators. It relates to the responsivity of a resonator's frequency to temperature variations and is typically quantified by the temperature coefficient of frequency (TCf). A constant and substantially large absolute TCf is preferred in MEMS temperature sensing applications, while a near-zero TCf is required for timing and other MEMS transducers that necessitate the decoupling of temperature effects on the resonance frequency. This comprehensive review aims to provide an in-depth overview of recent advancements in studying TCf in MEMS resonators. The review explores the compensation and engineering techniques employed across a range of resonator types, utilizing diverse materials. Various aspects are covered, including the design of MEMS resonators, theoretical analysis of TCf, temperature regulation techniques, and the metallization effect at high temperatures. The discussion encompasses TCf analysis of MEMS resonators operating in flexural, torsional, surface, and bulk modes, employing materials such as silicon (Si), lithium niobate (LiNbO3), silicon carbide (SiC), aluminum nitride (AlN), and gallium nitride (GaN). Furthermore, the review identifies areas that require continued development to fully exploit the TCf of MEMS resonators. 

Abstract The coupling between the spin degrees of freedom and macroscopic mechanical motions, including striction, shearing, and rotation, has attracted wide interest with applications in actuation, transduction, and information processing. Experiments so far have established the mechanical responses to the long‐range ordered or isolated single spin states. However, it remains elusive whether mechanical motions can couple to a different type of magnetic structure, the non‐collinear spin textures, which exhibit nanoscale spatial variations of spin (domain walls, skyrmions,etc.) and are promising candidates to realize high‐speed computing devices. Here, collective spin texture dynamics is detected with nanoelectromechanical resonators fabricated from 2D antiferromagnetic (AFM) MnPS₃with 10⁻⁹strain sensitivity. By examining radio frequency mechanical oscillations under magnetic fields, new magnetic transitions are identified with sharp dips in resonant frequency. They are attributed to collective AFM domain wall motions as supported by the analytical modeling of magnetostriction and large‐scale spin‐dynamics simulations. Additionally, an abnormally large modulation in the mechanical nonlinearity at the transition field infers a fluid‐like response due to ultrafast domain motion. The work establishes a strong coupling between spin texture and mechanical dynamics, laying the foundation for electromechanical manipulation of spin texture and developing quantum hybrid devices. 

Nanoelectromechanical systems (NEMS) incorporating atomic or molecular layer van der Waals materials can support multimode resonances and exotic nonlinear dynamics. Here we investigate nonlinear coupling of closely spaced modes in a bilayer (2L) molybdenum disulfide (MoS_2) nanoelectromechanical resonator. We model the response from a drumhead resonator using equations of two resonant modes with a dispersive coupling term to describe the vibration induced frequency shifts that result from the induced change in tension. We employ method of averaging to solve the equations of coupled modes and extract an expression for the nonlinear coupling coefficient (λ) in closed form. Undriven thermomechanical noise spectral measurements are used to calibrate the vibration amplitude of mode 2 (a_2) in the displacement domain. We drive mode 2 near its natural frequency and measure the shifted resonance frequency of mode 1 (f_1s) resulting from the dispersive coupling. Our model yields λ = 0.027 ± 0.005 pm^−2 · μs^−2 from thermomechanical noise measurement of mode 1. Our model also captures an anomalous frequency shift of the undriven mode 1 due to nonlinear coupling to the driven mode 2 mediated by large dynamic tension. This study provides a direct means to quantifying λ by measuring the thermomechanical noise in NEMS and will be valuable for understanding nonlinear mode coupling in emerging resonant systems. 

Nanoelectromechanical systems (NEMS) enabled by two-dimensional (2D) magnetic materials are promising candidates for exploring ultrasensitive detection and magnetostrictive phenomena, thanks to their high mechanical stiffness, high strength, and ultralow mass. The resonance modes of such vibrating membrane NEMS can be probed optically and also manipulated mechanically via electrostatically induced strain. Electrostatic frequency tuning of 2D magnetic NEMS resonators is, thus, an important means of investigating magneto-mechanical coupling mechanisms. Toward realizing magneto-mechanical coupled devices, we build circular drumhead iron phosphorus trisulfide (FePS3) NEMS resonators with different diameters (3–7 μm). Here, we report on experimental demonstration of tunable antiferromagnet FePS3 drumhead resonators with the highest fractional frequency tuning range up to Δf/f0 = 32%. Combining experimental results and analytical modeling of the resonance frequency scaling, we attain quantitative understanding of the elastic behavior of FePS3, including the transition from “membrane” to “plate” regime, with built-in tension (γ) ranging from 0.1 to 2 N/m. This study not only offers methods for investigating mechanical properties of ultrathin membranes of magnetic 2D materials but also provides important guidelines for designing future high-performance magnetic NEMS resonators. 

We report on the experimental demonstration of aluminum scandium nitride (AlScN)-on-cubic silicon carbide (3C-SiC) Lamb wave resonators (LWRs) realized via microelectromechanical systems (MEMS) technology, operating at high temperature (T) up to T = 800 °C, while retaining robust electromechanical resonances at ∼27 MHz and good quality factor of Q ≈ 900 even at 800 °C. Measured resonances exhibit clear consistency and stability during heating and cooling processes, validating the AlScN-on-SiC LWRs can operate at high T up to 800 °C without noticeable degradation in moderate vacuum (∼20 mTorr). Even after undergoing four complete thermal cycles (heating from 23 to 800 °C and then cooling down to 23 °C), the devices exhibit robust resonance behavior, suggesting excellent stability and suitability for high-temperature applications. Q starts to decline as the temperature exceeds 400 °C, which can be attributed to energy dissipation mechanisms stemming from thermoelastic damping and intrinsic material loss originating from phonon–phonon interactions. 

Parametric amplification of ultrasmall signals from electromechanical transducers directly in the mechanical domain, prior to electrical readout, is an intriguing challenge and is important for both scientific measurements and technologies utilizing micro/nanoelectromechanical systems (MEMS/NEMS). Here, we report on parametric amplification of aluminum nitride (AlN) multimode NEMS resonators (with broad intrinsic dynamic ranges up to 90 dB) for enabling detection of their thermomechanical resonances in both optical and electrical readout schemes simultaneously. The experiments demonstrate that, upon parametric pumping, the electrically transduced thermomechanical motions experience significant amplification, surpassing the extrinsic electronic noise level, while still below the parametric pumping threshold. We achieve noise matching that enables room temperature force sensitivity of 0.46 fN/Hz1/2. We observe high parametric gain up to 650, accompanied by a strong boost (over 3.5×) in the effective quality factor (Qeff, from 9000 to 32 000). These findings underscore the utilities of parametric amplification in noise matching and improving force sensitivity for NEMS transducers and their emerging applications. 

We report on the experimental demonstration of high-performance suspended channel transistors with single- and bilayer (1L and 2L) molybdenum disulfide (MoS2), and on operating them as vibrating channel transistors (VCTs) and exploiting their built-in dynamic electromechanical coupling to read out picoampere (pA) transconduction current directly at the vibrating tones, without frequency conversion or down-mixing, for picometer (pm)-scale motion detection at room temperature. The 1L- and 2L-MoS2 VCTs exhibit excellent n-type transistor behavior with high mobility [150 cm2/(V·s)] and small subthreshold swing (98 mV/dec). Their resonance motions are probed by directly measuring the small-signal drain-source currents (iD). Electromechanical characteristics of the devices are extracted from the measured iD, yielding resonances at f0 = 31.83 MHz with quality factor Q = 117 and f0 = 21.43 MHz with Q = 110 for 1L- and 2L-MoS2 VCTs, respectively. The 2L-MoS2 VCT demonstrates excellent current and displacement sensitivity (Si1/2 = 2 pA/Hz1/2 and Sx1/2 = 0.5 pm/Hz1/2). We demonstrate f0 tuning by controlling gate voltage VG and achieve frequency tunability Δf0/f0 ≈ 8% and resonance frequency change Δf0/ΔVG ≈ 0.53 kHz/mV. This study helps pave the way to realizing ultrasensitive self-transducing 2D nanoelectromechanical systems at room temperature, in all-electronic configurations, for on-chip applications.