Electrode configuration and electrical dissipation of mechanical energy in quartz crystal resonators

Abstract

Mechanical resonators made with monolithic piezoelectric quartz crystals are promising for studying new physical phenomena. High mechanical quality factors (Q) exhibited by the mm-sized quartz resonators make them ideal for studying weak couplings or long timescales in the quantum regime. However, energy losses through mechanical supports pose a serious limiting factor for obtaining high quality factors. Here we investigate how the Q of quartz resonators at deep cryogenic temperatures can be limited by several types of losses related to anchoring. We first introduce means to reduce the mechanical losses by more than an order of magnitude in a no-clamping scheme, obtaining Qfactors of 10 8 of the lowest shear mode. We can exclude a wide coverage of aluminum metallization on the disk or bond wires as sources of dissipation. However, we find a dramatic reduction of the Q-factor accompanying an electrode configuration that involves strong focusing of the vibrations in the disk center. We propose a circuit model that accounts for the reduced mechanical Q-factor in terms of electrical losses. In particular, we show how the limiting factor for losses can be small ohmic dissipation in a grounding connection, which can be interpreted as electrical anchor losses of the mechanical device.I.

Epitaxial bulk acoustic wave resonators as highly coherent multi-phonon sources for quantum acoustodynamics

“…Comparison with other HBAR and BAW resonators. Apart from the GaN/NbN/ SiC epi-HBAR data in this work, our study includes data reported in the literature from solid BAW overtone resonators fabricated from single-crystal bulk quartz, LiNbO 3 , and Si 6,7,17,24,25,42,[60][61][62] , as well as sputter-deposited HBARs on diamond 13,16,20,26,30 , fused silica 14 , quartz 14 , sapphire 5,14,15,21,27,28,63 , silicon 14,15,26,29 , and SiC 16,18,19,26 substrates. The sputter-deposited HBARs use polycrystalline piezoelectric AlN and ZnO thin films deposited on Al, Pt, Mo, and p + doped Si BE.…”

“…To systematically reduce net loss in the phonon cavity, it is necessary to reduce (if not eliminate) defect-based and interface-based phonon scattering. Many QAD experiments use bulk single-crystal overtone BAW resonators: massive macroscale devices with no internal interfaces and very low defect density 6,7,17,24,25 . However, such devices often require optomechanical actuation and are difficult to integrate into a compact system.…”

Detection Principles of Temperature Compensated Oscillators with Reactance Influence on Piezoelectric Resonator

“…The purpose of this study is to provide an overview of various ways of detection of physical quantities using oscillators with a piezoelectric crystal (as an oscillating element) and reactance connected in series or in parallel. The latter influences the crystal's electric substitute model and consequently its performance characteristics (the oscillating frequency near the resonance) [6][7][8]. The advantage of this method is great enhancement of sensor sensitivity, excellent temperature compensation, as well as compensation of capacitance among the crystal's electrodes and other parasitic impedances.…”