Superconducting gap, pseudogap, and fermi surface of Bi2201: High energy- and momentum-resolution photoemission study

We have performed a systematic high energy (7-11 meV) and momentum (0.01 An gstrom (-1)) resolution angle-resolved photoemission spectroscopy (ARPES) o n superstructure-free Bi1.80Pb0.38Sr2.01CuO6-delta With various dopings. Al l the samples from overdoped T-c=0K to underdoped T-c=18K possess a large h ole-like Fermi surface centered at X point, whose volume shows a systematic evolution with doping. The superconducting gap exhibits a d(x2-y2)-like an isotropy with a typical gap value of 10-15 meV. By comparing with Bi2Sr2CaC u2O8, we found that the size of superconducting gap and the ARPES spectral feature near EF are well scaled with the maximum T-c (T-c(max)). This sugge sts that the superconducting properties are characterized by T-c(max) irres pective of the number of CuO2 layers or the structural modulation in BiO la yer.