Doping evolution of the electronic structure in the single-layer cuprates Bi2Sr2−xLaxCuO6+δ: Comparison with other single-layer cuprates

We have performed angle-resolved photoemission and core-level x-ray photoemission studies of the single-layer cuprate Bi2Sr2−xLaxCuO6+δ (Bi2201) and revealed the doping evolution of the electronic structure from the lightly-doped to optimally-doped regions. We have observed the formation of the dispersive quasi-particle band, evolution of the Fermi “arc” into the Fermi surface and the shift of the chemical potential with hole doping as in other cuprates. The doping evolution in Bi2201 is similar to that in Ca2−xNaxCuO2Cl2 (Na-CCOC), where a rapid chemical potential shift toward the lower Hubbard band of the parent insulator has been observed, but is quite different from that in La2−xSrxCuO4 (LSCO), where the chemical potential does not shift, yet the dispersive band and the Fermi arc/surface are formed around the Fermi level already in the lightly-doped region. The (underlying) Fermi surface shape and band dispersions are quantitatively analyzed using tightbinding fit, and the deduced next-nearest-neighbor hopping integral t′ also confirm the similarity to Na-CCOC and the difference from LSCO.