标题： 通过微聚焦角分辨光电子能谱揭示电子掺杂铜氧化物超导体的非均匀还原-退火效应 显示英文标题

标题： Inhomogeneous reduction-annealing effects on the electron-doped cuprate superconductor revealed by micro-focused angle-resolved photoemission spectroscopy

摘要： 保护退火方法的发展将电子掺杂的铜氧化物超导体Pr$_{1.3-x}$La$_{0.7}$Ce$_{x}$CuO$_{4}$(PLCCO)的超导性扩展到更低的Ce浓度，同时随着欠掺杂，超导体积分数减少。 采用微聚焦束的角度分辨光电子能谱，我们研究了具有小超导体积分数的保护退火PLCCO ($x=0.08$)的电子结构。 观察到了费米面面积和形状的显著空间变化，表明电子浓度和与超导性竞争的赝隙存在不均匀性。 通过在数十个不同的样品位置进行测量，发现电子浓度和赝隙大小之间存在负相关和非单调相关。 建立的相关性说明了电子结构的系统退火依赖性，其中在氧还原不足时赝隙突然打开。 显示英文摘要

摘要： The development of the protect-annealing method has extended the superconductivity of the electron-doped cuprate Pr$_{1.3-x}$La$_{0.7}$Ce$_{x}$CuO$_{4}$ (PLCCO) into lower Ce concentrations, while the superconducting volume fraction decreases with underdoping. Employing angle-resolved photoemission spectroscopy with a micro-focused beam, we investigated the electronic structure of protect-annealed PLCCO ($x=0.08$) with small superconducting volume fraction. Significant spatial variation of Fermi surface area and shape was observed, suggesting inhomogeneity in electron concentrations and the pseudogap that competes with superconductivity. By performing measurements at dozens of different sample positions, negative and non-monotonic correlation was found between the electron concentration and pseudogap magnitude. The established correlation illustrates a systematic annealing dependence of the electronic structure where a pseudogap abruptly opens with insufficient oxygen reduction.