Superconductivity dichotomy in K-coated single and double unit cell FeSe films on SrTiO3

Abstract

We report the superconductivity evolution of one unit cell (1-UC) and 2-UC FeSe films on SrTiO3(001) substrates with potassium (K) adsorption. By in situ scanning tunneling spectroscopy measurement, we find that the superconductivity in 1-UC FeSe films is continuously suppressed with increasing K coverage, whereas non-superconducting 2-UC FeSe films become superconducting with a gap of ~17 meV or ~11 meV depending on whether the underlying 1-UC films are superconducting or not. This work explicitly reveals that the interface electron-phonon coupling is strongly related to the charge transfer at FeSe/STO interface and plays vital role in enhancing Cooper pairing in both 1-UC and 2-UC FeSe films.

References in corpus (3)

• Superconductivity in single-layer films of FeSe with a transition temperature above 100 K
• High temperature superconducting FeSe films on SrTiO3 substrates
• Oxygen Vacancy Induced Flat Phonon Mode at FeSe /SrTiO3 interface

Cited by in corpus (21)

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• The Role of SrTiO3 Phonon Penetrating into thin FeSe Films in the Enhancement of Superconductivity
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• Heterostructural one-unit-cell FeSe/SrTiO3: from high-temperature superconductivity to topological states
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• Electronic and phononic properties of a two dimensional electron gas coupled to dipolar phonons via small-momentum-transfer scattering
• 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
• Role of electric fields on enhanced electron correlation in surface-doped FeSe
• Modulation doping of the FeSe monolayer on SrTiO${}_3$
• Quantum Well Electronic States in Spatially Decoupled 2D Pb Nanoislands on Nb-doped SrTiO3(001)
• Suppression and revival of superconducting phase coherence in monolayer FeSe/SrTiO${}_3$
• Scanning tunneling microscopic evidence of interface enhanced high-Tc superconductivity in Pb islands grown on SrTiO3