Fermi Surface and Pseudogap Evolution in a Cuprate Superconductor

TL;DR

This study uses advanced microscopy to explore the relationship between the pseudogap and superconductivity in cuprates, revealing a Fermi surface reconstruction near optimal doping without affecting the pseudogap.

Contribution

It provides phase-sensitive evidence of coexistence of d-wave superconductivity and the pseudogap, and identifies a Fermi surface reconstruction close to optimal doping in cuprates.

Findings

Superconductivity coexists with the pseudogap on the antinodal Fermi surface.

Fermi surface reconstruction occurs slightly below optimal doping.

The pseudogap remains unaffected by the Fermi surface changes.

Abstract

The unclear relationship between cuprate superconductivity and the pseudogap state remains an impediment to understanding the high transition temperature (Tc) superconducting mechanism. Here we employ magnetic-field-dependent scanning tunneling microscopy to provide phase-sensitive proof that d-wave superconductivity coexists with the pseudogap on the antinodal Fermi surface of an overdoped cuprate. Furthermore, by tracking the hole doping (p) dependence of the quasiparticle interference pattern within a single Bi-based cuprate family, we observe a Fermi surface reconstruction slightly below optimal doping, indicating a zero-field quantum phase transition in notable proximity to the maximum superconducting Tc. Surprisingly, this major reorganization of the system's underlying electronic structure has no effect on the smoothly evolving pseudogap.