Electronic structure of rare-earth doped SrFBiS2 superconductors from photoemission spectroscopic studies

• Electronic structure study of Rare Earth (Ce and La) doped SrFBiS2 superconductors have been studied using photoemission spectroscopy and band structure calculations.
• Rare Earth doping promotes metallicity and the Fermi level is shifted towards conduction band.
• An enhanced spectral weight near EF accompanied by a reduced density of states at higher binding energy occurs for the doped compound.

The electronic structure study of the Rare Earth (La, Ce) doped SrFBiS2 superconductors using valence band photoemission in conjugation with the band structure calculations have been presented. The spectral features shift towards higher binding energy, consistent with the electron doping, for the doped compounds. An enhanced metallicity in addition to the shift in the Fermi level towards the conduction band occurs for the Rare Earth (RE) doped compounds. Further, the degeneracy of bands along X-M direction at valence band maximum (VBM) and conduction band minimum (CBM) is lifted due to RE doping. An enhanced spectral weight near EF accompanied by a decrease in density of states at higher binding energy occurs for the doped compounds. This unusual spectral weight shift is substantiated by the change in Fermi surface topology and reduced distortion of Bi-S plane for the doped compounds.