Superconductivity in mechanically exfoliated FeSe in the two-dimensional limit

The role of dimensionality in high-Tc superconductivity is an interesting issue—all known ambient-pressure high-Tc superconductors share a layered structure, even though superconductivity as a long-range order is not stable in two dimensions. Among these layered high-Tc superconductors, FeSe stands out with the simplest atomic structure; the high tunability makes it an ideal system for exploring high-Tc superconductivity in two-dimension. In this study, we successfully exfoliate FeSe single crystals down to monolayer, and investigate the evolution of superconductivity and nematicity in atomically thin FeSe flakes through transport measurements combined with scanning tunneling microscopy/spectroscopy. I will further discuss the effect of charge doping on the correlated phases in FeSe.