SPICE Workshop on Unconventional Superconductors and Magnets May 12th - 14th, 2026
Marie Wesson
Two-dimensional van der Waals (vdW) superconductors provide a clean platform for studying superconductivity and its fluctuations in the strict 2D limit. With electrostatic gating to tune carrier density, complex phase diagrams can be mapped in situ. Here we introduce an RF–microwave electrodynamics technique for vdW superconductors that measures the complex electrodynamic response across phase transitions. Unlike DC transport—which becomes insensitive to superconducting properties once the resistance vanishes—finite-frequency measurements directly probe the superfluid response (phase stiffness) and the dynamics of superconducting fluctuations. We apply this approach to monolayer WTe₂, where superconductivity emerges in proximity in carrier density to a quantum spin Hall insulating state at low temperatures. Tracking the electrodynamic response through the superconductor–insulator transition (SIT) in WTe₂ and deep into the superconducting state, we present a method for studying the two-fluid model through a density-tuned transition and extracting the complex conductance in the superconducting regime.