Strongly-coupled 2D membrane resonators in superconducting electromechanical circuits

Nanomechanical devices have allowed for the study of the motion of macroscopic objects near their quantum ground state for mechanical motion. Coupling these devices to resonant electrical circuits provides a method of measuring with standard laboratory electronics, and a means to interact and cool towards the ground state. We report on current work, in microwave $LC$ resonators, toward the use of graphene and niobium diselenide (NbSe$_2$) membranes as one electrode in a parallel plate capacitor with a mechanical degree of freedom. The membrane's light mass, non-linear response to an applied force and tunability potentially enable stronger electromechanical amplification and coupling. Previous work using graphene in similar systems shows that graphene's electrical resistance is a limiting factor when attempting to cool via electromechanical sideband interactions. In contrast, NbSe$_2$ is a superconductor even in single layer form, and this property has the potential to provide a system with lower loss while driving with increasing photon number, as compared to the graphene-based systems. In this talk we show fabrication, modelling and progress towards quantum-limited measurements.