Figure 3: Dichotomy of the electronic structure between the single-layer and double-layer FeSe/SrTiO 3 films.

The annealing condition corresponds to the sequence 10 in ref. 8. (a) Fermi surface of the annealed single-layer FeSe/SrTiO3 film. (b–d) Corresponding band structure of the annealed single-layer FeSe/SrTiO3 film along the Γ, M2 and M3 cuts, respectively. (e) Fermi surface of the annealed double-layer FeSe/SrTiO3 film. (f–h) Corresponding band structure of the annealed double-layer FeSe/SrTiO3 film along the Γ, M2 and M3 cuts, respectively. The band structures shown in (b–d) and (f–h) are second derivatives of the original band with respect to energy.