Suppression of antiferromagnetic order in the electron-doped cuprate T ′ − La 2 − x Ce x Cu O 4 ± δ

We performed systematic angle-resolved photoemission spectroscopy measurements in situ on ${T}^{\ensuremath{'}}\text{\ensuremath{-}}{\mathrm{La}}_{2\ensuremath{-}x}{\mathrm{Ce}}_{x}\mathrm{Cu}{\mathrm{O}}_{4\ifmmode\pm\else\textpm\fi{}\ensuremath{\delta}}$ (LCCO) thin films over the extended doping range prepared by the refined ozone/vacuum annealing method. Electron doping level ($n$), estimated from the measured Fermi surface (FS) volume, varied from 0.05 to 0.23, fully encompassing the superconducting dome. We observed an absence of the insulating behavior around $n\ensuremath{\sim}0.05$ and the shift of FS reconstruction to $n\ensuremath{\sim}0.11$ in LCCO from $n\ensuremath{\sim}0.15$ in other electron-doped cuprates, suggesting that the antiferromagnetic order is strongly suppressed in this material. The possible explanation may lie in the enhanced next-nearest-neighbor hopping in LCCO because of the largest ${\mathrm{La}}^{3+}$ ionic radius among all the lanthanide elements.