Local electronic structure of highly doped cuprate superconductors

Superconductivity in the unconventional, high-T_c cuprate superconductors emerges with sufficient hole-doping of the parent antiferromagnetic Mott insulating state. Upon further doping the superconductivity is eventually suppressed before fully breaking down. In this overdoped regime the superconducting state is thought to emerge from a more conventional Fermi liquid. The suppression of superconductivity would then follow a more BCS-like picture, with gap closure due to a vanishing pairing interaction. Here, we map the electronic structure and the superconducting gap of the single layer cuprate (Pb,Bi)₂Sr₂CuO_6+x using Spectroscoping Imaging Scanning Tunneling Microscopy and show how they evolve as T_c approaches zero in the overdoped regime. We find a highly heterogeneous electronic structure, with spectra with a gap and without a gap coexisting in close proximity at sufficiently high doping. Despite this strong inhomogeneity we still find a QPI signal consistent with full hole-like Fermi surfaces well-matched with ARPES results on the same samples. In this talk, I will discuss the implications of our data for the overdoped cuprates.