Orateur
Description
Superconducting films of amorphous indium oxide (a:InO) undergo a transition to an insulating state upon increasing disorder or magnetic field. The gradual suppression of the critical temperature as the disorder-driven transition is approached has long suggested a continuous collapse of the superfluid density, in line with the conventional picture of a continuous quantum phase transition. In this talk, I will show that this expectation fails: the disorder-tuned transition is instead marked by an abrupt jump of the superfluid density at the critical disorder, revealing a first-order quantum transition [1]. I will then turn to the magnetic-field-driven transition, where superconductivity survives in the form of a pinned vortex glass. Using microwave measurements of the superfluid response, I will show that interaction-driven collective vortex pinning strongly reshapes the field evolution of the stiffness, stabilizing superconductivity over an unexpectedly broad field range before its final collapse into an insulating state [2].
[1] T. Charpentier, D. Perconte, S. Léger, K. Amin, F. Blondelle, F. Gay, O. Buisson, L. Ioffe, A. Khvalyuk, I. Poboiko, M. Feigel’man, N. Roch, B. Sacépé, Nature Physics, 21, 104 (2025)
[2] D. Perconte, T. Charpentier, N. Koutsopoulos, K. roy, N. Benchabane, X. Peng, F. Blondelle, F. Gay, M. Feigel’man, V. Kabanov, B. Sacépé, arXiv:2605.23838 (2026)