Unconventional pairing in single FeSe layers

Abstract

The pairing mechanism in iron-based superconductors is believed to be unconventional, i.e. not phonon-mediated. The achieved transition temperatures Tc in these superconductors are still significantly below those of some of the cuprates, with the exception of single layer FeSe films on SrTiO3 showing a Tc between 60 and 100 K, i.e. an order of magnitude larger than in bulk FeSe. This enormous increase of Tc demonstrates the potential of interface engineering for superconductivity, yet the underlying mechanism of Cooper pairing is not understood. Both conventional and unconventional mechanisms have been discussed. Here we report a direct measurement of the electron-boson coupling function in FeSe on SrTiO3 using inelastic electron scattering which shows that the excitation spectrum becomes fully gapped below Tc strongly supporting a predominantly electronic pairing mechanism. We also find evidence for strong electron-phonon coupling of low energy electrons, which is however limited to regions near structural domain boundaries.

arXiv comment10 pages, 7 figures

References in corpus (42)

• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Interfacial mode coupling as the origin of the enhancement of Tc in FeSe films on SrTiO3
• Interface-induced superconductivity and strain-dependent spin density wave in FeSe/SrTiO3 thin films
• Superconductivity protected by spin-valley locking in ion-gated MoS2
• Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
• The effect of collective spin-1 excitations on electronic spectra in high-Tc superconductors
• Theory of magnetic excitations in iron-based layered superconductors
• Phonon-enhanced superconductivity at the FeSe/SrTiO3 interface
• Strong Interplay between Stripe Spin Fluctuations, Nematicity and Superconductivity in FeSe
• Critical role of substrate in the high temperature superconductivity of single layer FeSe on Nb:BaTiO${}_3$
• A relation between the resonance neutron peak and ARPES data in cuprates
• The neutron resonance: modeling photoemission and tunneling data in the superconducting state of Bi_2Sr_2CaCu_2O_{8+d}
• Monolayer FeSe on SrTiO${}_3$
• Plain s-wave superconductivity in single-layer FeSe on SrTiO3 probed by scanning tunneling microscopy
• Correlation of Tunneling Spectra in Bi2Sr2CaCu2O(8+delta) with the Resonance Spin Excitation
• Universal relation between magnetic resonance and superconducting gap in unconventional superconductors
• Extremely strong coupling superconductivity in artificial two-dimensional Kondo lattices
• Electronic Structure and Superconductivity of FeSe-Related Superconductors
• Superconducting gap anisotropy in monolayer FeSe thin film
• Universal Substrate Effect on the Superconductivity of FeSe Monolayer Films
• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
• The neutron resonance in the cuprates and its effect on fermionic excitations
• Ubiquitous strong electron phonon coupling at the interface of FeSe/SrTiO3
• High-temperature superconductivity in one-unit-cell FeSe films
• High Tc via spin fluctuations from incipient bands: application to monolayers and intercalates of FeSe
• Close relationship between superconductivity and the bosonic mode in Ba0.6K0.4Fe2As2 and Na(Fe0.975Co0.025)As
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• Oxygen Vacancy Induced Flat Phonon Mode at FeSe /SrTiO3 interface
• Local measurement of the Eliashberg function of Pb islands: enhancement of electron-phonon coupling by quantum well states
• Ab initio Study of Cross-Interface Electron-Phonon Couplings in FeSe Thin Films on SrTiO${}_3$ and BaTiO${}_3$
• Aspects of electron-phonon interactions with strong forward scattering in FeSe Thin Films on SrTiO${}_3$ substrates
• Odd parity pairing and nodeless anti-phase $s^{\pm }$ in Iron-Based Superconductors
• A compact ultrahigh vacuum scanning tunneling microscope with dilution refrigeration
• Imaging the Real Space Structure of the Spin Fluctuations in an Iron-based superconductor
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• Electronic structure of FeSe monolayer superconductors: shallow bands and correlations
• Tracing the electronic pairing glue in unconventional superconductors via inelastic Scanning Tunneling Spectroscopy
• Coupling to real and virtual phonons in tunneling spectroscopy of superconductors
• Strong coupling behavior of the neutron resonance mode in unconventional superconductors

Cited by in corpus (14)

• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Eliashberg theory for spin-fluctuations mediated superconductivity -- Application to bulk and monolayer FeSe
• Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states
• High-Temperature Majorana Fermions in Magnet-Superconductor Hybrid Systems
• Electronic and phononic properties of a two dimensional electron gas coupled to dipolar phonons via small-momentum-transfer scattering
• Multichannel superconductivity of monolayer FeSe on SrTiO${}_3$: Interplay of spin fluctuations and electron-phonon interaction
• Direct probing of a large spin-orbit coupling in the FeSe superconducting monolayer on STO: Evidence for nontrivial topological states
• Phase competition in a one-dimensional three-orbital Hubbard-Holstein model
• Direct evidence of a charge depletion region at the interface of Van der Waals monolayers and dielectric oxides: The case of superconducting FeSe/STO
• Effect of the additional Se layer on the electronic structure of iron-based superconductor FeSe/SrTiO${}_3$
• Bosonic excitation spectra of superconducting $\mathrm{B}{\mathrm{i}}_2\mathrm{S}{\mathrm{r}}_2\mathrm{CaC}{\mathrm{u}}_2{\mathrm{O}}_{8+\delta }$ and $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_{6+\mathrm{x}}$ extracted from scanning tunneling spectra
• Cavity quantum-electrodynamical polaritonically enhanced electron-phonon coupling and its influence on superconductivity
• Band structure of organic-ion-intercalated (EMIM)${}_x$FeSe superconductor
• Temperature evolution of the Fermi surface of the FeSe monolayer on SrTiO${}_3$