Dichotomy of Electronic Structure and Superconductivity between Single-Layer and Double-Layer FeSe/SrTiO3 Films

Abstract

The latest discovery of possible high temperature superconductivity in the single-layer FeSe film grown on a SrTiO3 substrate, together with the observation of its unique electronic structure and nodeless superconducting gap, has generated much attention. Initial work also found that, while the single-layer FeSe/SrTiO3 film exhibits a clear signature of superconductivity, the double-layer FeSe/SrTiO3 film shows an insulating behavior. Such a dramatic difference between the single-layer and double-layer FeSe/SrTiO3 films is surprising and the underlying origin remains unclear. Here we report our comparative study between the single-layer and double-layer FeSe/SrTiO3 films by performing a systematic angle-resolved photoemission study on the samples annealed in vacuum. We find that, like the single-layer FeSe/SrTiO3 film, the as-prepared double-layer FeSe/SrTiO3 film is insulating and possibly magnetic, thus establishing a universal existence of the magnetic phase in the FeSe/SrTiO3 films. In particular, the double-layer FeSe/SrTiO3 film shows a quite different doping behavior from the single-layer film in that it is hard to get doped and remains in the insulating state under an extensive annealing condition. The difference originates from the much reduced doping efficiency in the bottom FeSe layer of the double-layer FeSe/SrTiO3 film from the FeSe-SrTiO3 interface. These observations provide key insights in understanding the origin of superconductivity and the doping mechanism in the FeSe/SrTiO3 films. The property disparity between the single-layer and double-layer FeSe/SrTiO3 films may facilitate to fabricate electronic devices by making superconducting and insulating components on the same substrate under the same condition.

19 pages, 4 figures

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Cited by in corpus (39)

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• Common Electronic Origin of Superconductivity in (Li,Fe)OHFeSe Bulk Superconductor and Single-Layer FeSe/SrTiO3 Films
• Anomalous correlation effects and unique phase diagram of electron doped FeSe revealed by angle resolved photoemission spectroscopy
• Using Gap Symmetry and Structure to Reveal the Pairing Mechanism in Fe-based Superconductors
• Electronic Structure and Superconductivity of FeSe-Related Superconductors
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• Enhanced superconductivity due to forward scattering in FeSe thin films on SrTiO3 substrates
• High-Tc superconductivity in FeSe at high pressure: Dominant hole carriers and enhanced spin fluctuations
• Interface enhanced electron-phonon coupling and high temperature superconductivity in potassium-coated ultra-thin FeSe films on SrTiO3
• Antiferromagnetic ground state with pair-checkboard order in FeSe
• High-temperature superconductivity in one-unit-cell FeSe films
• Reemergence of high-Tc superconductivity in the (Li1-xFex)OHFe1-ySe under high pressure
• High Tc via spin fluctuations from incipient bands: application to monolayers and intercalates of FeSe
• Interface high-temperature superconductivity
• 20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal
• Oxygen Vacancy Induced Flat Phonon Mode at FeSe /SrTiO3 interface
• Thickness dependence of superconductivity and superconductor-insulator transition in ultrathin FeSe films on SrTiO3(001) substrate
• Gated Tuned Superconductivity and Phonon Softening in Mono- and Bilayer MoS${}_2$
• The role of double TiO2 layers at the interface of FeSe/SrTiO3 superconductors
• Antiferromagnetic order in epitaxial FeSe films on SrTiO3
• Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe${}_4$As${}_4$
• Aspects of electron-phonon interactions with strong forward scattering in FeSe Thin Films on SrTiO${}_3$ substrates
• On peculiarities of superconductivity in the single-layer FeSe/SrTiO3 interfa
• Effects of magnetic dopants in (Li${}_{0.8}$M${}_{0.2}$OH)FeSe (M = Fe, Mn, Co): a density-functional theory study using band unfolding technique
• Magnetic fluctuations and spin-spirals in single-layer FeSe
• Tuning stoichiometry and its impact on superconductivity of monolayer and multilayer FeSe on SrTiO3
• First-principles study of magnetic frustration in FeSe epitaxial films on SrTiO${}_3$
• Spin Fluctuation Induced Linear Magnetoresistance in Ultrathin Superconducting FeSe Films
• Band structure and charge doping effects of potassium-adsorbed FeSe/SrTiO3 system
• Effects of interface oxygen vacancies on electronic bands of FeSe/SrTiO3(001)
• Twisted-bilayer FeSe and the Fe-based superlattices
• Superconducting transition of FeSe/SrTiO3 induced by adsorption of semiconducting organic molecules
• Electronic structure and nematic phase transition in superconducting multi-layer FeSe films grown by pulsed laser deposition method
• Identification of a Large Amount of Excess Fe in Superconducting Single-Layer FeSe/SrTiO3 Films
• First-principles study of FeSe epitaxial films on SrTiO3
• Insulating Parent Phase and Distinct Doping Evolution to Superconductivity in Single-Layer FeSe/SrTiO3 Films
• Pomeranchuk instability in the nematic phase of two monolayer FeSe/SrTiO3