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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. 

Abstract 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 (MoS₂) 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 (a₂) 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 yieldsλ = 0.027 ± 0.005 pm⁻² · μs⁻²from 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 quantifyingλby 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. 

Abstract 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⁻¹are 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 TCfcan 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. 

Photonic quantum information processing and communication demand highly integrated device platforms, which can offer high-fidelity control of quantum states and seamless interface with fiber-optic networks simultaneously. Exploiting the unique quantum emitter characteristics compatible with photonic transduction, combined with the outstanding nonlinear optical properties of silicon carbide (SiC), we propose and numerically investigate a single-crystal cubic SiC-on-insulator (3C-SiCOI) platform toward multi-functional integrated quantum photonic circuit. Benchmarking with the state-of-the-art demonstrations on individual components, we have systematically engineered and optimized device specifications and functions, including state control via cavity quantum electrodynamics and frequency conversion between quantum emission and telecommunication wavelengths, while also considering the manufacturing aspects. This work will provide concrete guidelines and quantitative design considerations for realizing future SiCOI integrated photonic circuitry toward quantum information applications. 

Abstract Beta gallium oxide (β‐Ga₂O₃) has emerged as a highly promising semiconductor material with an ultrawide bandgap ranging from 4.5 to 4.9 eV for future applications in power electronics, optoelectronics, as well as gas and ultraviolet (UV) radiation sensors. Here, surface adsorption and air damping behavior of doubly clamped β‐Ga₂O₃nanomechanical resonators are probed and systemically studied by measuring the resonance characteristics under different gas and pressure conditions. High responsivities of resonance to pressure are obtained by heating the devices up to 300 °C to induce an accelerated adsorption–desorption process. The initial surface conditions of the β‐Ga₂O₃thin film play important roles in affecting the resonant behavior. UV ozone treatment proves effective in altering the initial surface conditions of β‐Ga₂O₃nanosheets by eliminating physisorbed contaminants and filling oxygen vacancy defects residing on the surface, resulting in a consequential and discernible modification of the resonance behavior of β‐Ga₂O₃nanomechanical resonators. The surface adsorption and desorption processes in β‐Ga₂O₃demonstrate clear reversibility by exposing the UV treated β‐Ga₂O₃to air. This study attains first‐hand information on how the surface conditions of β‐Ga₂O₃affect its mechanical properties, and helps guide future development of transducers via β‐Ga₂O₃nanoelectromechanical systems (NEMS) for pressure sensing applications, especially in harsh environments. 

Advances in creating polar structures in atomic‐layered hafnia‐zirconia (Hf_xZr_1−xO₂) films not only augurs extensive growth in studying ferroelectric nanoelectronics and neuromorphic devices, but also spurs opportunities for exploring novel integrated nanoelectromechanical systems (NEMS). Design and implementation of Hf_xZr_1−xO₂NEMS transducers necessitates accurate knowledge of elastic and electromechanical properties. Up to now, all experimental approaches for extraction of morphological content, elastic, and electromechanical properties of Hf_xZr_1−xO₂are based on solidly mounted structures, highly stressed films, and electroded architectures. Unlike Hf_xZr_1−xO₂layers embedded in electronics, NEMS transducers require free‐standing structures with highly contrasted mechanical boundaries and stress profiles. Here, a nanoresonator‐based approach for simultaneous extraction of Young's modulus and residual stress in free‐standing ferroelectric Hf_0.5Zr_0.5O₂films is presented. High quality factor resonance modes of nanomechanical resonators created in predominantly orthorhombic Hf_0.5Zr_0.5O₂films are measured using nondestructive optical transduction. Further, the evolution of morphology during creation of free‐standing Hf_0.5Zr_0.5O₂structures is closely mapped using X‐ray diffraction measurements, clearly showing transformation of ferroelectric orthorhombic to nonpolar monoclinic phase upon stress relaxation. The extracted Young's modulus of 320.0 ± 29.4 GPa and residual stress ofσ = 577.4 ± 24.1 MPa show the closest match with theoretical calculations for orthorhombic Hf_0.5Zr_0.5O₂.