标题： 镨掺杂的YBa$_2$Cu$_3$O$_{7-δ}$中超导性的抑制和双层解耦 显示英文标题

标题： Superconductivity suppression and bilayer decoupling in Pr substituted YBa$_2$Cu$_3$O$_{7-δ}$

摘要： Pr取代导致YBa$_2$Cu$_3$O$_{7-\delta}$（YBCO）超导性抑制的机制自发现以来一直是个谜：尽管它与Y$^{3+}$是等价的，具有较小的磁矩，但它是唯一对YBCO超导性质有显著影响的稀土元素。 使用角分辨光电子能谱（ARPES）和DFT+$U$计算，我们揭示了Pr取代如何改变YBCO的低能电子结构。 与普遍的Fehrenbacher-Rice（FR）和Liechtenstein-Mazin（LM）模型相反，低能电子结构中没有任何$f$-电子杂化或新态的特征。 然而，主要在反键费米面观察到强烈的电子掺杂。 同时，我们揭示了随着Pr取代的增加，Cu衍生态的主要电子结构变化：明显的CuO$_2$双层解耦和增强的CuO链跳跃，表明存在超越简单4$f$状态电离的间接电子释放路径。 我们的结果挑战了长期存在的FR/LM机制，并确立Pr掺杂的YBCO作为探索耦合一维-二维系统中关联驱动现象的潜在平台。 显示英文摘要

摘要： The mechanism behind superconductivity suppression induced by Pr substitutions in YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) has been a mystery since its discovery: in spite of being isovalent to Y$^{3+}$ with a small magnetic moment, it is the only rare-earth element that has a dramatic impact on YBCO's superconducting properties. Using angle-resolved photoemission spectroscopy (ARPES) and DFT+$U$ calculations, we uncover how Pr substitution modifies the low-energy electronic structure of YBCO. Contrary to the prevailing Fehrenbacher-Rice (FR) and Liechtenstein-Mazin (LM) models, the low energy electronic structure contains no signature of any $f$-electron hybridization or new states. Yet, strong electron doping is observed primarily on the antibonding Fermi surface. Meanwhile, we reveal major electronic structure modifications to Cu-derived states with increasing Pr substitution: a pronounced CuO$_2$ bilayer decoupling and an enhanced CuO chain hopping, implying indirect electron-release pathways beyond simple 4$f$ state ionization. Our results challenge the long-standing FR/LM mechanism and establish Pr substituted YBCO as a potential platform for exploring correlation-driven phenomena in coupled 1D-2D systems.