Presentation Information
[10a-E207-6]Suspended lithium niobate resonator cavities in single phonon regime for quantum applications
〇(P)Michele Diego1, Hong Qiao2, Byunggi Kim3, Minseok Ryu2, Shiheng Li4, Gustav Andersson2, Masahiro Nomura1, Andrew N. Cleland2 (1.IIS, Univ. of Tokyo, 2.PME, Univ. of Chicago, 3.Inst. of Science Tokyo, 4.Dept. of Physics, Univ. of Chicago)
Keywords:
Nanomechanics,Acoustic devices,Quantum acoustics
Phonons combine strong confinement within matter with broad coupling capabilities to a variety of physical systems. In particular, piezoelectric materials such as lithium niobate can be used to couple gigahertz-frequency acoustic waves to superconducting qubits. As a result, acoustic piezoelectric nanodevices offer a promising route toward hybrid acoustic quantum technologies. However, bulk phononic devices typically rely on surface acoustic waves, which are subject to leakage from the surface into the underlying substrate. Here, we study resonator cavities fabricated on suspended lithium niobate membranes (Fig. 1), supporting Lamb waves that avoid acoustic leakage into the substrate. The devices are characterized at both room and millikelvin temperatures, in different circuit configurations, while theoretical simulations are performed to rationalize the resonant mode profiles and resonance frequencies. At millikelvin temperatures, operation at the single-phonon level is achieved, revealing an intrinsic quality factor of 6000. These measurements enable us to model the coupling between our resonators and superconducting qubits, providing design guidelines for future quantum acoustic devices.