The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity

Abstract

The significant role of interfacial coupling on the superconductivity enhancement in FeSe films on SrTiO3 has been widely recognized. But the explicit origination of this coupling is yet to be identified. Here by surface phonon measurements using high resolution electron energy loss spectroscopy, we found electric field generated by Fuchs-Kliewer (F-K) phonon modes of SrTiO3 can penetrate into FeSe films and strongly interact with electrons therein. The mode-specific electron-phonon coupling (EPC) constant for the ~92 meV F-K phonon is ~0.25 in the single-layer FeSe on SrTiO3. With increasing FeSe thickness, the penetrating field intensity decays exponentially, which matches well the observed exponential decay of the superconducting gap. It is unambiguously shown that the SrTiO3 F-K phonon penetrating into FeSe is essential in the interfacial superconductivity enhancement.

Main text: 6 pages, 3 figures; Supplementary Material: 8 pages, 6 figures. An error in the EPC constant calculation was corrected in this version and several new references are added. The authors would like to thank Dr. Yan Wang (University of Tennessee) for pointing out the error

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Cited by in corpus (41)

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• Phonon-enhanced superconductivity at the FeSe/SrTiO3 interface
• Monolayer FeSe on SrTiO${}_3$
• Computation and data driven discovery of topological phononic materials
• Origin of charge transfer and enhanced electron-phonon coupling in single unit-cell FeSe films on SrTiO3
• Dynamic interfacial polaron enhanced superconductivity of FeSe/SrTiO3
• High-temperature superconductivity in one-unit-cell FeSe films
• Measurement of the dynamic charge response of materials using low-energy, momentum-resolved electron energy-loss spectroscopy (M-EELS)
• Interface high-temperature superconductivity
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• Ultrafast Quasiparticle Dynamics and Electron-Phonon Coupling in (Li0.84Fe0.16)OHFe0.98Se
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
• Detection of bosonic mode as a signature of magnetic excitation in one unit cell FeSe on SrTiO3
• Ferroelectricity-tuned band topology and superconductivity in two-dimensional materials and related heterostructures
• Interfacial Electron-Phonon Coupling Constants Extracted from Intrinsic Replica Bands in Monolayer FeSe/SrTiO${}_3$
• Unconventional pairing in single FeSe layers
• Electronic and phononic properties of a two dimensional electron gas coupled to dipolar phonons via small-momentum-transfer scattering
• Intrinsic interfacial van der Waals monolayers and their effect on the high-temperature superconductor FeSe/SrTiO${}_3$
• Phonon linewidth due to electron-phonon interactions with strong forward scattering in FeSe thin films on oxide substrates
• Phonon Boost Effect on the $S^{\pm }$-wave Superconductor with Incipient Band
• Anharmonic theory of superconductivity and its applications to emerging quantum materials
• Soft phonons in the interface layer of the STO substrate can explain high temperature superconductivity in one unit cell FeSe
• Direct probing of a large spin-orbit coupling in the FeSe superconducting monolayer on STO: Evidence for nontrivial topological states
• Superconducting transition of FeSe/SrTiO3 induced by adsorption of semiconducting organic molecules
• Identification of a Large Amount of Excess Fe in Superconducting Single-Layer FeSe/SrTiO3 Films
• Hybrid nodal surface and nodal line phonons in solids
• Dispersionless orbital excitations in (Li,Fe)OHFeSe superconductors
• Superconductivity of the FeSe/SrTiO3 Interface in the View of BCS-BEC Crossover
• Insulating Parent Phase and Distinct Doping Evolution to Superconductivity in Single-Layer FeSe/SrTiO3 Films
• The Hidden Nematic Fluctuations in the Triclinic (Ca0.85La0.15)10(Pt3As8)(Fe2As2)5 Superconductor Revealed by Ultrafast Optical Spectroscopy
• 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
• Direct evidence of a charge depletion region at the interface of Van der Waals monolayers and dielectric oxides: The case of superconducting FeSe/STO
• Pressure-induced superconductivity in itinerant antiferromagnet CrB2
• Studies of superconductivity of Fe chalcogenides in films grown by PLD technique
• LaO as a candidate substrate for realizing superconductivity in FeSe epitaxial film
• Inferior interfacial superconductivity in 1 UC FeSe/SrVO${}_3$/SrTiO${}_3$ with screened interfacial electron-phonon coupling
• Temperature evolution of the Fermi surface of the FeSe monolayer on SrTiO${}_3$
• Dual Enhancement of Superconductivity in FeSe/SrTiO3 via Orbital and Correlation Synergy