Picoscale structural insight into superconductivity of monolayer FeSe/SrTiO3
Open Access
- 1 April 2020
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science Advances
- Vol. 6 (15), eaay4517
- https://doi.org/10.1126/sciadv.aay4517
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.Funding Information
- U.S. Department of Energy (DE-AC02-06CD11357)
- U.S. Department of Energy (DESC0012704)
- Air Force Office of Scientific Research (FA9550-15-1-0472)
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