Coexistence of high temperature superconductivity and antiferromagnetic order in a cuprate with multiple hole Fermi pockets

The intricate relationship between high temperature superconductivity and antiferromagnetic order in cuprates, and the fundamental origin of electron pairing remain open questions. By utilizing high-resolution laser-based spatially-resolved angle-resolved photoemission spectroscopy, we investigate the seven-layer Bi2Sr2Ca6Cu7O18+δ (Bi2267) and identify a cuprate system that consists of multiple hole Fermi pockets. The observed Fermi pockets exhibit pronounced momentum-, temperature- and Fermi surface-dependent energy gaps. Crucially, high temperature superconductivity with a critical temperature (Tc) of ~ 75 K emerges in a system with multiple Fermi pockets and the presence of strong antiferromagnetic order and correlations. In particular, substantial electron pairing is observed along the Fermi pocket with an energy gap up to ~ 42 meV in lightly-doped CuO2 planes (p ~ 0.05). These findings challenge the conventional understanding of the roles of the nodal and antinodal electronic states in driving high temperature superconductivity. They show that superconductivity and antiferromagnetism can coexist in a cuprate with multiple Fermi pockets, offering further insights into the pairing mechanism in cuprate superconductors. The authors study cuprate superconductor Bi2Sr2Ca6Cu7O18+δ with seven CuO2 planes in the unit cell, finding multiple hole-like Fermi pockets in the (π/2,π/2) nodal region. They observe strong electron pairing with an energy gap as high as ~ 42 meV on one of the highly-underdoped inner planes where a robust antiferromagnetic order persists.