Superconducting Circuits for Probing Moiré Materials

Twisted trilayer graphene (TTG) hosts gate-tunable correlated insulating and superconducting phases, yet the microscopic mechanism underlying its superconductivity remains unclear. Microwave measurements provide a powerful route to probe TTG's electrodynamic response and collective dynamics, complementing conventional transport measurements. We build a coplanar waveguide (CPW) resonator shorted to ground through a TTG channel and extract the superfluid stiffness via kinetic-inductance induced resonance shifts. The carrier density is tuned electrostatically using a back gate with an integrated on-chip low-pass filter. The resonator and filter geometries are optimized through finite-element electromagnetic simulations in Ansys HFSS and AWR Microwave Office. This platform enables systematic measurement of superfluid stiffness as a function of carrier density and temperature, by analyzing power-dependent resonance frequencies and quality factors. The device provides a robust microwave probe of gate-tunable superconductivity in Moiré materials. We present the device design, simulation results, and preliminary microwave measurements on mirror-symmetric TTG.