No Arabic abstract
Nanoscale electromechanical coupling provides a unique route towards control of mechanical motions and microwave fields in superconducting cavity electromechanical devices. Though their successes in utilizing the optomechanical or electromechanical back-action effects for various purposes, aluminum imposes severe constraints on their operating conditions with its low superconducting critical temperature (1.2 K) and magnetic field (0.01 T). To extend the potential of the devices, here we fabricate a superconducting electromechanical device employing niobium and demonstrate a set of cavity electromechanical dynamics including back-action cooling and amplification, and electromechanically induced reflection at 4.2 K and in strong magnetic fields up to 0.8 T. This device could be used to realize electromechanical microwave components for quantum technologies by integrating amplifiers, converters, and circulators on a single chip that can be installed at the 4K stage of dilution refrigerators. Moreover, with its ability to control and readout nanomechanical motions simultaneously, this niobium electromechanical transducer could provide powerful nanomechanical sensing platforms.
High kinetic inductance materials constitute a valuable resource for superconducting quantum circuits and hybrid architectures. Superconducting granular aluminum (grAl) reaches kinetic sheet inductances in the nH/$square$ range, with proven applicability in superconducting quantum bits and microwave detectors. Here we show that the single photon internal quality factor $Q_{mathrm{i}}$ of grAl microwave resonators exceeds $10^5$ in magnetic fields up to 1T, aligned in-plane to the grAl films. Small perpendicular magnetic fields, in the range of 0.5mT, enhance $Q_{mathrm{i}}$ by approximately 15%, possibly due to the introduction of quasiparticle traps in the form of fluxons. Further increasing the perpendicular field deteriorates the resonators quality factor. These results open the door for the use of high kinetic inductance grAl structures in circuit quantum electrodynamics and hybrid architectures with magnetic field requirements.
The unique properties and atomic thickness of two-dimensional (2D) materials enable smaller and better nanoelectromechanical sensors with novel functionalities. During the last decade, many studies have successfully shown the feasibility of using suspended membranes of 2D materials in pressure sensors, microphones, accelerometers, and mass and gas sensors. In this review, we explain the different sensing concepts and give an overview of the relevant material properties, fabrication routes, and device operation principles. Finally, we discuss sensor readout and integration methods and provide comparisons against the state of the art to show both the challenges and promises of 2D material-based nanoelectromechanical sensing.
A high Q-factor microwave resonator in a high magnetic field could be used in a wide range of applications, especially for enhancing the scanning speed in axion dark matter research. In this letter, we introduce a polygon-shaped resonant cavity with commercial YBCO tapes covering the entire inner wall. We demonstrated that the maximum Q-factor (TM$_{010}$, 6.93 GHz) of the superconducting YBCO cavity was about 6 times higher than that of a copper cavity and showed no significant degradation up to 8 T at 4 K. This is the first indication of the possible applications of HTS technology to the research areas requiring low loss in a strong magnetic field at high radio frequencies.
Superconducting coplanar waveguide resonators that can operate in strong magnetic fields are important tools for a variety of high frequency superconducting devices. Magnetic fields degrade resonator performance by creating Abrikosov vortices that cause resistive losses and frequency fluctuations, or suppressing superconductivity entirely. To mitigate these effects we investigate lithographically defined artificial defects in resonators fabricated from NbTiN superconducting films. We show that by controlling the vortex dynamics the quality factor of resonators in perpendicular magnetic fields can be greatly enhanced. Coupled with the restriction of the device geometry to enhance the superconductors critical field, we demonstrate stable resonances that retain quality factors $simeq 10^5$ at the single photon power level in perpendicular magnetic fields up to $B_perp simeq$ 20 mT and parallel magnetic fields up to $B_parallel simeq$ 6 T. We demonstrate the effectiveness of this technique for hybrid systems by integrating an InSb nanowire into a field resilient superconducting resonator, and use it to perform fast charge readout of a gate defined double quantum dot at $B_parallel =$ 1 T.
Nanoelectromechanical system (NEMS) sensors and actuators could be of use in the development of next generation mobile, wearable, and implantable devices. However, these NEMS devices require transducers that are ultra-small, sensitive and can be fabricated at low cost. Here, we show that suspended double-layer graphene ribbons with attached silicon proof masses can be used as combined spring-mass and piezoresistive transducers. The transducers, which are realized using processes that are compatible with large-scale semiconductor manufacturing technologies, can yield NEMS accelerometers that occupy at least two orders of magnitude smaller die area than conventional state-of-the-art silicon accelerometers.