Atomically Resolved FeSe/SrTiO3(001) Interface Structure by Scanning Transmission Electron Microscopy

Abstract

Interface-enhanced high-temperature superconductivity in one unit-cell (UC) FeSe films on SrTiO3(001) (STO) substrate has recently attracted much attention in condensed matter physics and material science. By combined in-situ scanning tunneling microscopy/spectroscopy (STM/STS) and ex-situ scanning transmission electron microscopy (STEM) studies, we report on atomically resolved structure including both lattice constants and actual atomic positions of the FeSe/STO interface under both non-superconducting and superconducting states. We observed TiO2 double layers (DLs) and significant atomic displacements in the top two layers of STO, lattice compression of the Se-Fe-Se triple layer, and relative shift between bottom Se and topmost Ti atoms. By imaging the interface structures under various superconducting states, we unveil a close correlation between interface structure and superconductivity. Our atomic-scale identification of FeSe/STO interface structure provides useful information on investigating the pairing mechanism of this interface-enhanced high-temperature superconducting system.

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Cited by in corpus (24)

• Monolayer FeSe on SrTiO${}_3$
• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Origin of charge transfer and enhanced electron-phonon coupling in single unit-cell FeSe films on SrTiO3
• Incoherent Cooper pairing and pseudogap behavior in single-layer FeSe/SrTiO${}_3$
• The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors
• Antiferromagnetic order in epitaxial FeSe films on SrTiO3
• Ab initio Study of Cross-Interface Electron-Phonon Couplings in FeSe Thin Films on SrTiO${}_3$ and BaTiO${}_3$
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• Does a pristine, unreconstructed SrTiO${}_3$(001) surface exist?
• Tuning stoichiometry and its impact on superconductivity of monolayer and multilayer FeSe on SrTiO3
• Intrinsic interfacial van der Waals monolayers and their effect on the high-temperature superconductor FeSe/SrTiO${}_3$
• Visualization of local magnetic moments emerging from impurities in the Hund's metal states of FeSe
• Soft phonons in the interface layer of the STO substrate can explain high temperature superconductivity in one unit cell FeSe
• Twisted-bilayer FeSe and the Fe-based superlattices
• Identification of a Large Amount of Excess Fe in Superconducting Single-Layer FeSe/SrTiO3 Films
• Magic Doping and Robust Superconductivity in Monolayer FeSe on Titanates
• The phonon mechanism explanation of the superconductivity dichotomy between FeSe and FeS monolayers on STO and other substrates
• Imaging Se diffusion across the FeSe/SrTiO${}_3$ interface
• Modulation doping of the FeSe monolayer on SrTiO${}_3$
• Higher-order epitaxy: A pathway to suppressing structural instability and emergent superconductivity
• Effect of the additional Se layer on the electronic structure of iron-based superconductor FeSe/SrTiO${}_3$
• Sublattice Dichotomy in Monolayer FeSe Superconductor
• Unconventional incommensurate epitaxy of superconducting FeSe films on SrTiO${}_3$