Figure 3: Superconducting gap.
From: Enhanced superconductivity accompanying a Lifshitz transition in electron-doped FeSe monolayer
(a–c) Temperature evolution of the symmetrized EDCs at the kF point of the electron FS around M for pristine and potassium-coated 1UC FeSe/STO. The electron doping is indicated above the panels. The red curves correspond to fit of the data. (d–f) Superconducting gap sizes as a function of temperature obtained from the fits shown in a–c, respectively. Error bars are estimated from the standard deviation (s.d.) of the fitting. (g) Schematic FS of K-coated 1UC FeSe/STO with doping x∼0.212. (h) Upper part: temperature evolution of the EDCs at Γ divided by the FD function. Lower part: low temperature EDCs further divided by the one at 70 K. (i) Symmetrized EDCs at 14 K measured at various kF points as indicated by coloured dots in g. (j) Polar representation of the momentum dependence of the superconducting gap size for the electron FS around M. Error bars again are estimated from s.d. of the fitting. A nearly isotropic gap is highlighted by the dashed grey circle at 15 meV.
