Universal Substrate Effect on the Superconductivity of FeSe Monolayer Films

Abstract

To elucidate the mechanisms behind the enhanced $T_c$ in monolayer (1ML) FeSe on SrTiO${}_3$ (STO), we grew highly strained 1ML FeSe on the rectangular (100) face of rutile TiO${}_2$, and observed the coexistence of replica bands and superconductivity with a $T_c$ of 63 K. From the similar $T_c$ between this system and 1ML FeSe on STO (001), we conclude that strain and dielectric constant are likely unimportant to the enhanced $T_c$ in these systems. A systematic comparison of 1ML FeSe on TiO${}_2$ with other systems in the FeSe family shows that while charge transfer alone can enhance $T_c$, it is only with the addition of interfacial electron-phonon coupling that $T_c$ can be increased to the level seen in 1ML FeSe on STO.

5 pages, 3 figures

References in corpus (2)

• Superconductivity at 27 K in tetragonal FeSe under high pressure
• Reconstruction of Band Structure Induced by Electronic Nematicity in an FeSe Superconductor

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• Magnetically brightened dark electron-phonon bound states in a van der Waals antiferromagnet
• Lattice Dynamics of Ultrathin FeSe Films on SrTiO3
• Eliashberg theory for spin-fluctuations mediated superconductivity -- Application to bulk and monolayer FeSe
• Observation of a two-dimensional electron gas at CaTiO${}_3$ film surfaces
• Plain $s$-wave superconductivity near the magnetic criticality: Enhancement of attractive electron-boson coupling vertex corrections
• Magic Doping and Robust Superconductivity in Monolayer FeSe on Titanates
• Molecular Beam Epitaxy Growth of Tetragonal FeS Film on SrTiO3(001) Substrate
• LaO as a candidate substrate for realizing superconductivity in FeSe epitaxial film
• Robustness of superconducting properties to transition metal substitution and impurity phases in Fe1-xVxSe