High temperature superconductivity at FeSe/LaFeO(3) interface

Enormous enhancement of superconducting pairing temperature (T(g)) to 65 K in FeSe/SrTiO(3) has made it a spotlight. Despite the effort of interfacial engineering, FeSe interfaced with TiO(x) remains the unique case in hosting high T(g), hindering a decisive understanding on the general mechanism and ways to further improving T(g). Here we constructed a new high-T(g) interface, single-layer FeSe interfaced with FeO(x)-terminated LaFeO(3). Large superconducting gap and diamagnetic response evidence that the superconducting pairing can emerge near 80 K, highest amongst all-known interfacial superconductors. Combining various techniques, we reveal interfacial charge transfer and strong interfacial electron-phonon coupling (EPC) in FeSe/LaFeO(3), showing that the cooperative pairing mechanism works beyond FeSe-TiO(x). Intriguingly, the stronger interfacial EPC than that in FeSe/SrTiO(3) is likely induced by the stronger interfacial bonding in FeSe/LaFeO(3), and can explain the higher T(g) according to recent theoretical calculations, pointing out a workable route in designing new interfaces to achieve higher T(g).