Extended superconducting dome revealed by angle-resolved photoemission spectroscopy of electron-doped cuprates prepared by the protect annealing method

Abstract

The electron-doped cuprates are usually characterized by a more robust antiferromagnetic phase and a much narrower superconducting (SC) dome than those of the hole-doped counterparts. Recently, bulk single crystals of Pr_{1.3−x}La_{0.7}Ce_{x}CuO_{4−δ} (PLCCO) prepared by the protect annealing method have been studied extensively and revealed many intriguing properties that were different from those obtained from samples annealed by the conventional methods. Here we report on a systematic angle-resolved photoemission spectroscopy study of PLCCO single crystals after protect annealing. The results indicate that the actual electron concentration (n_{FS}) estimated from the Fermi-surface area is significantly larger than the Ce concentration x and the new n_{FS}-based SC dome of PLCCO is more extended towards the overdoped side than the x-based SC dome derived for samples prepared using the conventional annealing method.