On the Tc enhancement mechanism at the FeSe/SrTiO3 interface

At the interface between monolayer FeSe films and STO substrate the superconducting transition temperature (Tc) is unexpectedly high. The mechanism for the Tc enhancement has been the central question, as it may present a new strategy for seeking out higher Tc materials.
To reveal the mechanism, by combining advances in high quality interface growth, ¹⁶O-¹⁸O isotope substitution, and extensive data from angle resolved photoemission spectroscopy, we provide striking evidence that the high Tc in FeSe/STO is the cooperative effect of the intrinsic pairing mechanism in the FeSe and interactions between the FeSe electrons and STO phonons.
Furthermore, our results point to the promising prospect that similar cooperation between different Cooper pairing channels may be a general framework to understand and design HTSCs.