Suppression of the antiferromagnetic pseudogap in the electron-doped high-temperature superconductor by protect annealing.
Suppression of the antiferromagnetic pseudogap in the electron-doped high-temperature superconductor by protect annealing.
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DOI：
10.1038/ncomms10567
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发表时间：
2016-02-04
影响因子：
16.6
通讯作者：
Fujimori A
中科院分区：
文献类型：
--
作者：
Horio M;Adachi T;Mori Y;Takahashi A;Yoshida T;Suzuki H;Ambolode LC 2nd;Okazaki K;Ono K;Kumigashira H;Anzai H;Arita M;Namatame H;Taniguchi M;Ootsuki D;Sawada K;Takahashi M;Mizokawa T;Koike Y;Fujimori A
在空穴掺杂的铜氧化物中，少量的载流子抑制反铁磁性并诱导超导电性。另一方面，在电子掺杂的铜氧化物中，仅在还原退火后的高掺杂Ce浓度的窄窗口中出现超导性，并且在超导相中存在强的反铁磁关联。最近，Pr1.3−xLa0.7CexCuO4（PLCCO）大块单晶通过保护退火方法退火，对于低至0.05的小Ce含量显示出约27 K的高临界温度。在这里，通过角分辨光电子能谱测量PLCCO晶体，我们观察到一个尖锐的准粒子峰在整个费米表面上没有签名的反铁磁赝隙不同于所有以前的工作，表明反铁磁相关长度和/或磁矩的显着减少。超导状态被发现在很宽的电子浓度范围内延伸。目前的研究结果从根本上挑战了长期以来的电子结构在电子掺杂制度的图片。在高电子掺杂浓度下，铜氧化物的超导电性存在于一个狭窄的窗口中，具有强的反铁磁关联。在这里，作者证明了超导性，没有反铁磁顺序的影响，在铜酸盐的宽电子掺杂范围后的保护退火过程。
In the hole-doped cuprates, a small number of carriers suppresses antiferromagnetism and induces superconductivity. In the electron-doped cuprates, on the other hand, superconductivity appears only in a narrow window of high-doped Ce concentration after reduction annealing, and strong antiferromagnetic correlation persists in the superconducting phase. Recently, Pr1.3−xLa0.7CexCuO4 (PLCCO) bulk single crystals annealed by a protect annealing method showed a high critical temperature of around 27 K for small Ce content down to 0.05. Here, by angle-resolved photoemission spectroscopy measurements of PLCCO crystals, we observed a sharp quasi-particle peak on the entire Fermi surface without signature of an antiferromagnetic pseudogap unlike all the previous work, indicating a dramatic reduction of antiferromagnetic correlation length and/or of magnetic moments. The superconducting state was found to extend over a wide electron concentration range. The present results fundamentally challenge the long-standing picture on the electronic structure in the electron-doped regime. In cuprates, superconductivity exists in a narrow window at high electron doping concentration with strong antiferromagnetic correlations. Here, the authors demonstrate superconductivity with no effect of antiferromagnetic order in a cuprate for a wide electron doping range following a protect anneal process.