Crystallographic suppression of bulk wave coupling in surface acoustic wave (SAW) resonators on quartz

By joining long-lived mechanical resonators with superconducting circuits, the burgeoning field of circuit quantum acoustodynamics (cQAD) has in recent years demonstrated increasingly impressive quantum control over phonons. However, owing to their reliance on piezoelectric media which may inadvertently couple to spurious acoustic modes, these systems have suffered from qubit lifetimes two orders of magnitude shorter than those on more favorable dielectrics. Here we report on efforts to mitigate piezoelectric qubit losses in hybrid cQAD platforms through crystallographic engineering. In particular, we use finite element simulations to search for orientations of quartz which inherently suppress bulk wave coupling in SAW resonators. Although our focus is on surface wave devices, this technique is readily extendable to other hybrid piezoelectric platforms.