Interface high-temperature superconductivity

Abstract

Cuprate high temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high temperature superconductivity in ultrathin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high temperature superconductivity with a superconducting gap of ~20 meV in 1UC-FeSe/STO has stimulated tremendous interest in superconductivity community, for it opens new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high temperature superconductivity. Here, we review mainly the experimental progress on interface enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and possible pairing mechanism inferred from those studies.

14 pages, 8 figures

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Cited by in corpus (23)

• Unconventional Superconductivity
• 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
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• A Cleanroom in a Glovebox
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• An extensive impurity-scattering study on the pairing symmetry of monolayer FeSe films on SrTiO3
• Absence of Magnetic Fluctuations in the Ferromagnetic/Topological Heterostructure EuS/Bi${}_2$Se${}_3$
• Self-consistent temperature dependence of quasiparticle bands in monolayer FeSe on SrTiO${}_3$
• Coexistence of Superconductivity and Antiferromagnetism in Topological Magnet MnBi2Te4 Films
• Competing superconducting phases in interacting two-dimensional electron gas with strong Rashba spin-orbit coupling
• Soft phonons in the interface layer of the STO substrate can explain high temperature superconductivity in one unit cell FeSe
• Identification of a Large Amount of Excess Fe in Superconducting Single-Layer FeSe/SrTiO3 Films
• Possible spin excitation structure in monolayer FeSe grown on SrTiO${}_3$
• Multifaceted impact of a surface step on superconductivity in atomically thin films
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• The phonon mechanism explanation of the superconductivity dichotomy between FeSe and FeS monolayers on STO and other substrates
• Tuning monolayer superconductivity in twisted NbSe${}_2$ graphene heterostructures
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