Different classes of low-dimensional superconducting systems exhibit an inhomogeneous filamentary superconducting condensate whose macroscopic coherence still needs to be fully investigated and understood. Here we present a thorough analysis of the superfluid response of a prototypical filamentary superconductor embedded in a {two-dimensional} metallic matrix. By mapping the system into an exactly solvable random impedance network, we show how the dissipative (reactive) response of the system non-trivially depends on both the macroscopic and microscopic characteristics of the metallic (superconducting) fraction. We compare our calculations with resonant-microwave transport measurements performed on LaAlO3/SrTiO3 heterostructures over an extended range of temperatures and carrier densities finding that the filamentary character of superconductivity accounts for unusual peculiar features of the experimental data.
@article{arxiv.2304.07117,
title = {Superfluid response of two-dimensional filamentary superconductors},
author = {Giulia Venditti and Ilaria Maccari and Alexis Jouan and Gyanendra Singh and Ramesh C. Budhani and Cheryl Feuillet-Palma and Jérôme Lesueur and Nicolas Bergeal and Sergio Caprara and Marco Grilli},
journal= {arXiv preprint arXiv:2304.07117},
year = {2023}
}