Mapping Local Superfluid Density on Inhomogeneous Superconductor

Two-dimensional material heterostructures offer the ability to manipulate superconductivity via tunable parameters including carrier density, strain, and interlayer coupling. However, the reduced dimensionality of these systems, their small sample volumes, and the need for local probes present significant challenges in understanding how superconductivity can be modified through heterostructure design. Previously, magnetic force microscopy (MFM) has been used to measure the local magnetic penetration depth, 𝜆 [1]. In this work, we extend this technique to study thin and inhomogeneous superconductors. By combining MFM measurements with modeling of Meissner screening currents, we spatially map out 𝜆 and demonstrate how this technique can be applied to measure local modifications of superfluid density enabled by heterostructure engineering.

[1] L. Luan, O. M. Auslaender, T. M. Lippman, C. W. Hicks, B. Kalisky, J.-H. Chu, J. G. Analytis, I. R. Fisher, J. R. Kirtley, and K. A. Moler, Phys. Rev. B 81, 100501 (2010).