Interplay between hole superconductivity and quantum critical antiferromagnetic fluctuations in electron-doped cuprates.

Antiferromagnetic spin fluctuations are the most promising candidate as the pairing glue of high critical temperature (T) superconductivity in cuprates. However, many-body states and intertwined orders have made it difficult to determine how electrons couple with fluctuating spins to form Cooper pairs. Recent experimental and theoretical studies have suggested spin fluctuation-driven quasiparticle band folding, but the relationship between the resultant Fermi pockets and superconductivity remains unclear. Here, using angle-resolved photoemission spectroscopy and numerical simulations, we show a proportional relationship between T and the quasiparticle weight of the incipient hole pocket near the nodal point in electron-doped PrLaCeCuO. Through complementary muon spin spectroscopy measurements, we uncover that the hole pocket forms only in the regime of the fluctuating antiferromagnetic ground state around a presumed quantum critical point. Our observations highlight the significance of the electron-spin fluctuation interaction in enhancing the hole pocket and consequently driving superconductivity.