Suppression of Antiferromagnetism in Electron-Doped Cuprate $T'$-${\rm La}_{2-x}{\rm Ce}_x\rm {CuO}_{4\pmδ}$

Abstract: We performed systematic angle-resolved photoemission spectroscopy measurements $in$-$situ$ on $T'$-${\rm La}{2-x}{\rm Ce}_x\rm {CuO}{4\pm\delta}$ (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 volume, varies from 0.05 to 0.23, which covers the whole superconducting dome. We observed an absence of the insulating behavior around $n \sim$ 0.05 and the Fermi surface reconstruction shifted to $n \sim$ 0.11 in LCCO compared to that of other electron-doped cuprates at around 0.15, suggesting that antiferromagnetism is strongly suppressed in this material. The possible explanation may lie in the enhanced -$t'$ /$t$ in LCCO for the largest $\rm{La^{3+}}$ ionic radius among all the Lanthanide elements.