Probing Quantum Materials using Scanning SQUID Microscopy

Competition or cooperation between different electronic orders with similar energy scales often gives rise to new or unexpected behaviors. Detecting traces of such orders requires versatile probes, which can probe different aspects of the system, such as conductivity, superconductivity and magnetism. In my talk, I will describe two systems where our local view uncovered surprising mesoscopic effects. One is an oxide interface, where we imaged the current flow close to a metal-to-insulator transition. We found that the critical behavior is controlled by the structure rather than by universal scaling laws. The other system is a van-der Waals material in which we found a hidden magnetic phase, revealed by a spontaneous vortices hosted by the superconductor. Overall, our results highlight the power of scanning SQUID microscopy in probing the properties of quantum materials and providing local insights into their behavior.