Picoscale structural insight into superconductivity of monolayer FeSe/SrTiO3.

ABSTRACT: Remarkable enhancement of the superconducting transition temperature (T c) has been observed for monolayer (ML) FeSe films grown on SrTiO3 substrates. The atomic-scale structure of the FeSe/SrTiO3 interface is an important determinant of both the magnetic and interfacial electron-phonon interactions and is a key ingredient to understanding its high-T c superconductivity. We resolve the atomic-scale structure of the FeSe/SrTiO3 interface through a complementary analysis of scanning transmission electron microscopy and in situ surface x-ray diffraction. We find that the interface is more strongly bonded for a particular registration, which leads to a coherently strained ML. We also determine structural parameters, such as the distance between ML FeSe and the oxide, Se?Fe?Se bond angles, layer-resolved distances between Fe?Se, and registry of the FeSe lattice relative to the oxide. This picoscale structure determination provides an explicit structural framework and constraint for theoretical approaches addressing the high-T c mechanism in FeSe/SrTiO3.

SUBMITTER: Peng R 

PROVIDER: S-EPMC7141823 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature