Incipient hole pocket-driven superconductivity in the electron-doped cuprate Pr_1−xLaCe_xCuO_4±δ

Determination of spin-fluctuation induced quasiparticle renormalization and establishing its link with superconductivity is a long-standing unresolved issue in high-T_c cuprate research. Here, to address this issue, we performed angle-resolved photoemission spectroscopy on the electron-doped cuprate Pr_1−xLaCe_xCuO_4±δ with doping spanning the regime of fluctuating antiferromagnetic ground states around a presumed quantum critical point. Through the function fitting analysis, we resolved the single-particle nodal band spectrum into the antiferromagnetically folded hole band and the unfolded pristine band components, accounting for the strong electron correlation effect. By tracking the doping evolution of the antiferromagnetic peak at the folding center, we uncovered that the peak is gapped from the Fermi level across the entire phase diagram, while partial crossings to the Fermi energy are observed only in the superconducting region. This partial crossing of the folded hole band evidences a fluctuating nature of incipient Fermi hole pocket, attributed to the electron-spin fluctuation coupling. More importantly, we found that T_c is negatively and positively correlated with the gap and the zero-energy spectral weight of the peak, respectively. In this presentation, we will discuss the role of antiferromagnetic quantum critical fluctuations in enhancing the hole pocket and consequently driving the superconductivity.