Fermi surface reconstruction in electron-doped cuprates without antiferromagnetic long-range order

Abstract

Significance Fermi surface (FS) topology is a fundamental property of metals and superconductors. In electron-doped cuprate Nd 2− x Ce x CuO 4 , an unexpected FS reconstruction has been observed in optimal- and overdoped regime ( x = 0.15 − 0.17) by quantum oscillation measurements (QOM). This is puzzling because neutron scattering suggests that the antiferromagnetic long-range order, which is believed to reconstruct the FS, vanishes before x = 0.14. Here, we report angle-resolved photoemission evidence of FS reconstruction. The observed FSs are in quantitative agreement with QOM, suggesting an intrinsic FS reconstruction without field. Furthermore, the energy gap of the reconstruction decreases rapidly near x = 0.17 like an order parameter, echoing the quantum critical doping in transport. The totality of the data points to a mysterious order between x = 0.14 and 0.17.