Interface enhanced electron-phonon coupling and high temperature superconductivity in potassium-coated ultra-thin FeSe films on SrTiO3

Abstract

Alkali-metal (potassium) adsorption on FeSe thin films with thickness from two unit cells (UC) to 4-UC on SrTiO3 grown by molecular beam epitaxy is investigated with a low-temperature scanning tunneling microscope. At appropriate potassium coverage (0.2-0.3 monolayer), the tunneling spectra of the films all exhibit a superconducting-like gap larger than 11 meV (five times the gap value of bulk FeSe), and two distinct features of characteristic phonon modes at 11 meV and 21 meV. The results reveal the critical role of the interface enhanced electron-phonon coupling for possible high temperature superconductivity in the system and is consistent with recent theories. Our study provides compelling evidence for the conventional pairing mechanism for this type of heterostructure superconducting systems.

References in corpus (14)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6
• Plain s-wave superconductivity in single-layer FeSe on SrTiO3 probed by scanning tunneling microscopy
• Electron-lattice interaction and its impact on high Tc superconductivity
• Doping dependence of the coupling of electrons to bosonic modes in the single-layer high-temperature Bi2Sr2CuO6 superconductor
• Origin of the large phonon band-gap in SrTiO3 and the vibrational signatures of ferroelectricity in ATiO3 perovskite: First principles lattice dynamics and inelastic neutron scattering of PbTiO3, BaTiO3 and SrTiO3
• Onset of the Meissner effect at 65 K in FeSe thin film grown on Nb doped SrTiO3 substrate
• Neutron scattering Measurements of the phonon density of states of FeSe${}_{1-x}$ superconductors
• Evidence of a spin resonance mode in the iron-based superconductor Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ from scanning tunneling spectroscopy
• Anomalous Raman scattering from phonons and electrons of superconducting FeSe${}_{0.82}$
• Superconductivity dichotomy in K-coated single and double unit cell FeSe films on SrTiO3
• Phonon, Two-Magnon and Electronic Raman Scattering of Fe1+yTe1-xSex
• Thickness-Dependent Coherent Phonon Frequency in Ultrathin FeSe/SrTiO${}_3$ Films

Cited by in corpus (36)

• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)
• Monolayer FeSe on SrTiO${}_3$
• Two-dimensional Superconductors with Atomic-scale Thicknesses
• Observation of Double-Dome Superconductivity in Potassium-Doped FeSe Thin Films
• Universal Substrate Effect on the Superconductivity of FeSe Monolayer Films
• Origin of charge transfer and enhanced electron-phonon coupling in single unit-cell FeSe films on SrTiO3
• What makes the Tc of monolayer FeSe on SrTiO3 so high: a sign-problem-free quantum Monte Carlo study
• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
• Ubiquitous strong electron phonon coupling at the interface of FeSe/SrTiO3
• High-temperature superconductivity in one-unit-cell FeSe films
• Interface high-temperature superconductivity
• Atomically Resolved FeSe/SrTiO3(001) Interface Structure by Scanning Transmission Electron Microscopy
• Superconductivity dichotomy in K-coated single and double unit cell FeSe films on SrTiO3
• Multiband full-bandwidth anisotropic Eliashberg theory of interfacial electron-phonon coupling and high-T${}_c$ superconductivity in FeSe/SrTiO${}_3$
• Superconductivity and Nematic Fluctuations in a model of FeSe monolayers: A Determinant Quantum Monte Carlo Study
• Incommensurate smectic phase in close proximity to the high-Tc superconductor FeSe/SrTiO3
• Detection of bosonic mode as a signature of magnetic excitation in one unit cell FeSe on SrTiO3
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
• Simultaneous emergence of superconductivity, inter-pocket scattering and nematic fluctuation in potassium-coated FeSe superconductor
• Eliashberg theory for spin-fluctuations mediated superconductivity -- Application to bulk and monolayer FeSe
• An extensive impurity-scattering study on the pairing symmetry of monolayer FeSe films on SrTiO3
• Interplay of screening and superconductivity in low-dimensional materials
• Bounds on Nanoscale Nematicity in Single-Layer FeSe/SrTiO${}_3$
• Proposal for a bulk material based on a monolayer FeSe on SrTiO3 high-temperature superconductor
• Antiferromagnetism enables electron-phonon coupling in iron-based superconductors
• Superconductivity in 2D electron gas induced by high energy optical phonon mode and large polarization of the STO substrate
• Soft phonons in the interface layer of the STO substrate can explain high temperature superconductivity in one unit cell FeSe
• Superconducting transition of FeSe/SrTiO3 induced by adsorption of semiconducting organic molecules
• Structural and electronic properties of ultrathin FeSe films grown on Bi${}_2$Se${}_3$(0001) studied by STM/STS
• Pairing enhanced by local orbital fluctuations in a model for monolayer FeSe
• Insulating Parent Phase and Distinct Doping Evolution to Superconductivity in Single-Layer FeSe/SrTiO3 Films
• Interface suppressed nematicity and enhanced superconductivity of FeSe/NdFeO3 in the low doping regime
• The phonon mechanism explanation of the superconductivity dichotomy between FeSe and FeS monolayers on STO and other substrates
• Studies of superconductivity of Fe chalcogenides in films grown by PLD technique
• Inferior interfacial superconductivity in 1 UC FeSe/SrVO${}_3$/SrTiO${}_3$ with screened interfacial electron-phonon coupling