Disentangling Bulk from Surface Loss in 2D Superconducting Archimedean Spiral Resonators 

In recent years, advances in materials and fabrication have fueled the improvement of superconducting qubits. However, these devices are often limited by energy dissipated within the dielectric materials of which they are partially composed. To probe dominant sources of dielectric loss within these devices, we investigate 2D superconducting Archimedean Spiral Resonators (ASRs). These ASRs can be designed to have lower electric field participation in the surfaces compared to typical coplanar waveguide geometries, enabling a more precise differentiation of bulk from surface loss. We present a technique to delineate these two sources of loss by utilizing ASRs of varied geometries as well as their higher modes. Our study utilizes ASRs fabricated on different substrates and with varied materials and processing techniques, measured over a range of temperatures and microwave powers. This work informs strategies for fabricating qubits with improved error rates.