Integration of High-Tc Superconductors with High Q Factor Oxide Mechanical Resonators

Abstract

Micro-mechanical resonators are building blocks of a variety of applications in basic science and applied electronics. This device technology is mainly based on well-established and reproducible silicon-based fabrication processes with outstanding performances in term of mechanical Q factor and sensitivity to external perturbations. Broadening the functionalities of MEMS by the integration of functional materials is a key step for both applied and fundamental science. However, combining functional materials and silicon-based compounds is challenging. An alternative approach is fabricating MEMS based on complex heterostructures made of materials inherently showing a variety of physical properties such as transition metal oxides. Here, we report on the integration of a high-Tc superconductor YBa2Cu3O7 (YBCO) with high Q factor micro-bridge resonator made of a single-crystal LaAlO3 (LAO) thin film. LAO resonators are tensile strained, with a stress of 345 MPa, show Q factor in the range of tens of thousands, and have low roughness. The topmost YBCO layer deposited by Pulse Laser Deposition shows a superconducting transition starting at 90 K with zero resistance below 78 K. This result opens new possibilities towards the development of advanced transducers, such as bolometers or magnetic field detectors, as well as basic science experiments in solid state physics, material science, and quantum opto-mechanics.