Insulating Parent Phase and Distinct Doping Evolution to Superconductivity in Single-Layer FeSe/SrTiO3 Films

Abstract

The single-layer FeSe/SrTiO3 (FeSe/STO) films have attracted much attention because of their simple crystal structure, distinct electronic structure and record high superconducting transition temperature (Tc). The origin of the dramatic Tc enhancement in single-layer FeSe/STO films and the dichotomy of superconductivity between single-layer and multiple-layer FeSe/STO films are still under debate. Here we report a comprehensive high resolution angle-resolved photoemission spectroscopy and scanning tunneling microscopy/spectroscopy measurements on the electronic structure evolution with doping in single-layer and multiple-layer FeSe/STO films. We find that the single-layer FeSe/STO films have a distinct parent phase and a route of doping evolution to superconductivity that are fundamentally different from multiple-layer FeSe/STO films. The parent phase of the single-layer FeSe/STO films is insulating, and its doping evolution is very similar to that of doping a Mott insulator in cuprate superconductors. In multiple-layer FeSe/STO films, high-Tc superconductivity occurs by suppressing the nematic order in the parent compound with electron doping. The single-layer FeSe/STO films represent the first clear case in the iron-based superconductors that the parent compound is an insulator. Our observations of the unique parent state and doping evolution in the single-layer FeSe/STO films provide key insight in understanding its record high-Tc superconductivity. They also provide a new route of realizing superconductivity in iron-based superconductors that is common in high temperature cuprate superconductors.

References in corpus (36)

• Superconductivity in Iron Compounds
• 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
• Kinetic frustration and the nature of the magnetic and paramagnetic states in iron pnictides and iron chalcogenides
• 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
• Extreme Sensitivity of Superconductivity to Stoichiometry in FeSe (Fe1+dSe)
• Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
• The Structural Phase Transition in FeSe (Fe1+dSe)
• Structure determination and coexistence of superconductivity and antiferromagnetic order in (Li0.8Fe0.2)OHFeSe
• Electronic correlations in the iron pnictides
• Evidence for electron-electron interaction in topological insulator thin films
• Missing Quasiparticles and the Chemical Potential Puzzle in the Doping Evolution of the Cuprate Superconductors
• Reconstruction of Band Structure Induced by Electronic Nematicity in an FeSe Superconductor
• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)
• Monolayer FeSe on SrTiO${}_3$
• Neutron Studies of the Iron-based Family of High TC Magnetic Superconductors
• Electronic Structure and Superconductivity of FeSe-Related Superconductors
• Observation of Double-Dome Superconductivity in Potassium-Doped FeSe Thin Films
• Onset of the Meissner effect at 65 K in FeSe thin film grown on Nb doped SrTiO3 substrate
• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
• Atomic and electronic structures of FeSe monolayer and bilayer thin films on SrTiO${}_3$ (001): a first-principles study
• Interface enhanced electron-phonon coupling and high temperature superconductivity in potassium-coated ultra-thin FeSe films on SrTiO3
• New Li-Ethylenediamine-Intercalated Superconductor Li${}_x$(C${}_2$H${}_8$N${}_2$)${}_y$Fe${}_{2-z}$Se${}_2$ with $T_c$ = 45 K
• Electronic Evidence of an Insulator-Superconductor Transition in Single-Layer FeSe/SrTiO3 Films
• Disappearance of Nodal Gap across the Insulator-Superconductor Transition in a Copper-Oxide Superconductor
• Antiferromagnetic ground state with pair-checkboard order in FeSe
• High-temperature superconductivity in one-unit-cell FeSe films
• Dichotomy of Electronic Structure and Superconductivity between Single-Layer and Double-Layer FeSe/SrTiO3 Films
• Interface high-temperature superconductivity
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• 20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
• Antiferromagnetic order in epitaxial FeSe films on SrTiO3
• Simultaneous emergence of superconductivity, inter-pocket scattering and nematic fluctuation in potassium-coated FeSe superconductor
• Identification of a Large Amount of Excess Fe in Superconducting Single-Layer FeSe/SrTiO3 Films

Cited by in corpus (2)

• Checkerboard order state in superconducting FeSe/SrTiO3(001) monolayer
• Imaging Se diffusion across the FeSe/SrTiO${}_3$ interface