Towards scanning tunneling spectroscopy of iron-based superconducting van der Waals heterostructures

Iron-based superconductors (FeSCs) set a new paradigm of unconventional superconductivity, owing to their multiorbital nature. Since the discovery of FeSCs, a range of exotic phenomena, including Hund's correlation, magnetism, nematicity, quantum criticality, and non-trivial topology, alongside superconductivity, have been established in this material platform. Despite the significance of both fundamental physics and potential applications on quantum technology, previous measurements were mainly focused on studying bulk crystals, and so far, potentially important quantum effects in finite-size samples have remained to a large degree unexplored. In this talk, we will discuss our efforts to measure exfoliated thin flakes of Fe(Te,Se) using scanning tunneling microscopy and spectroscopy that reveal the presence of multiple well resolved superconducting gaps highlighting high sample quality. Our approach provides a novel opportunity to acquire deeper insights into the nature of the superconductivity of this system and provides a necessary step for potentially controlling Majorana zero mode hosted in superconducting vortices.